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Bulk File RenamerRename and organise hundreds of files at once.eSignDoceSignDoc runs a complete DocuSign-style signing workflow in five stages: upload your document, share aExcel Formula ExtractorUpload an Excel workbook (.xlsx, .xls, .xlsm or .xltx/.xltm) and this tool scans every sheet for formulasFile CompressorShrink images and files so they upload faster, email easily and take less space.File ConverterConvert images, documents and spreadsheets between popular formats without installing anything.File Converter HubThis page lists every conversion pair available in the AZRS file converter, grouped by type: image convertersFile Encryption ToolThis tool covers four related jobs in one interface, switched with a mode tab: encrypt a file with aImage to PDF ConverterTurn JPG, PNG and other images into a single PDF in seconds.Office File ConverterA general-purpose file converter that covers a wide grid of source and target formats in one interface: pickPDF MergerCombine several PDF files into one document in a few clicks.PDF SplitterSplit a PDF into single pages or pull out just the pages you need.Text ExtractorThis text extractor pulls readable text out of more than 25 file formats: scanned images and photos (OCR inVideo DownloaderPaste a video URL and this tool fetches its metadata first — title, uploader, thumbnail, view count, uploadBackground RemoverUpload a photo and this tool automatically detects the subject and removes everything behind it, giving you aForeground RemoverThis is the mirror image of a background remover: instead of keeping the subject and dropping the backgroundImage Color ChangerThis tool swaps specific colours in an image for new ones, driven by click-to-select colour pairs rather thanImage ResizerResize any JPG, PNG or WebP image using exact pixel dimensions, a percentage scale, or ready-made presetsAI HumanizerMake stiff, robotic text read like natural human writingAI Paraphrasing ToolThis paraphraser uses AI to rewrite your text while preserving its meaning, in one of 10 styles — StandardAI Text DetectorCheck text for AI-writing signals — free, in your browserAI Text SummarizerPaste text or upload a TXT, DOCX or PDF file (up to 10 MB) and get a concise summary in seconds.AI Text to SpeechTurn text into spoken audio with AI voices.AI TranslatorTranslate text, documents and images between many languages.ASCII Art GeneratorTurn text into large ASCII banner letters, or a photo into ASCII artAudio to Text ConverterTranscribe audio or video to text with AI Whisper.Binary & Text ConverterConvert text to and from four different number bases — binary, hexadecimal, octal and decimal — using aBinary / Hex / ASCII Text TranslatorConvert text to and from binary, hexadecimal and decimal ASCII codesBraille TranslatorTranslate English text to and from Grade 1 Braille Unicode patternsCase ConverterPaste any text and instantly convert it into more than 30 formats: everyday cases like UPPERCASE, lowercaseFancy Text GeneratorTurn plain text into 𝓯𝓪𝓷𝓬𝔂 Unicode stylesFind & Replace ToolRun multiple find-and-replace rules on a block of text at once, entirely in your browser.Lorem Ipsum GeneratorGenerate placeholder text for mockups, wireframes and design reviews in seconds.Markdown EditorWrite Markdown in a split-pane editor and watch the rendered HTML preview update instantly on the other sideMorse Code TranslatorTranslate text to Morse code and back, with audioNATO Phonetic Alphabet TranslatorSpell out any word using the NATO phonetic alphabet (Alpha, Bravo, Charlie…)Number to Words ConverterWrite numbers and amounts in wordsOnline NotesA private notes app for quick capture and organization: create notes with a title, color and type, pin theParaphrasing ToolReword sentences with new word choicesRandom Name & Username GeneratorGenerate random first names, full names or usernames instantlyRandom Quote GeneratorGet an inspiring, funny or thoughtful random quote, filterable by categoryRemove Duplicate Lines & Sort TextDedupe, sort, trim and reverse linesResume / CV Builder + ATS Score CheckerBuild a resume with a live preview, then score it against ATS parsing rulesRoman Numeral ConverterConvert numbers to Roman numerals and backText CleanerRemove extra spaces, blank lines and formatting junkText Diff CheckerPaste two versions of a text — two drafts, two code snippets, or two config files — and see exactly whatText Reverser & FlipperReverse text, words, lines or flip it upside downText to SpeechConvert written text into clear, natural-sounding audio in seconds.Typing Speed TestTest your typing speed (WPM) and accuracy with 12,000+ sentencesWord CounterThis word counter goes beyond a simple word tally.Word Search Puzzle GeneratorType a list of words and get a printable word search puzzle grid with a matching answer keyQR Code GeneratorGenerate a fully customised QR code from any text or URL, then style it far beyond a plain black-and-whiteAge CalculatorCalculate exact age in years, months and days between a birth date and any target date (usually today).Amazon FBA Profit CalculatorReal per-item profit and margin for Amazon FBA, with the fulfillment fee auto-calculated from your weight and dimensionsAppliance Electricity Cost CalculatorEstimate how much it costs to run an appliance based on its wattage, hours used and your rateBig Mac Index Currency ComparatorCompare real purchasing power between countries using The Economist's real published Big Mac Index dataBill Splitter & Tip CalculatorSplit a bill and tip between any number of peopleBMI CalculatorCalculate your Body Mass Index (BMI) from your height and weight, in either metric (cm/kg) or imperialBody Fat Percentage CalculatorEstimate body fat percentage using the US Navy circumference methodBreathing Exercise TimerA guided breathing pacer for box breathing and 4-7-8 breathingBusiness Days CalculatorCount business days, calendar days and working hours between two dates, aware of real public holidays for 100+ countriesCalorie & TDEE CalculatorDaily calories to lose, maintain or gain weightCompound Interest CalculatorCalculate how a lump sum or a regularly contributed savings amount grows with compound interest over time.Countdown Timer & StopwatchOnline countdown timer, stopwatch and lap timerCredit Card Payoff Calculator — Minimum vsSee the real interest and time you save by paying more than the minimum on one credit cardCurrency ConverterConvert between world currencies using up-to-date exchange rates.Daily Water Intake CalculatorHow much water should you drink each day?Days Between Dates CalculatorCount days, weeks and months between datesDebt Payoff CalculatorCompare the snowball and avalanche methods to pay off multiple debtsDiscount CalculatorWork out the sale price and the amount you save on any discounted item.DoorDash / Uber Eats Commission CalculatorReal restaurant delivery-platform commission by service tier, auto-calculated into your net revenue per ordereBay Fee CalculatorReal eBay final value fee and net payout, auto-calculated from your sale price and categoryEtsy Fee CalculatorReal Etsy listing, transaction, payment processing and ad fees, auto-summed from your sale priceEV Charging Cost CalculatorReal electric vehicle charging cost per charge, per mile and per tripEvent Countdown Page CreatorBuild a live countdown to any date — wedding, launch, birthday — with an embeddable snippetExpense TrackerLog spending against a monthly budget in your browser, no account needed.Expense Tracker DashboardTrack income, spending, budgets, goals and debts in one account.Expense Tracker: AccountsKeep several accounts, transfer between them and track who owes you.Expense Tracker: BudgetsSet spending limits and see budget alerts.Expense Tracker: CategoriesSee spending by category and add your own categories.Expense Tracker: Debts and BillsTrack debts, see a payoff plan and keep repeating bills.Expense Tracker: Goals and WishlistSave toward goals and keep a wishlist.Expense Tracker: Monthly ReportA spending calendar, weekly view and biggest expenses for the month.Expense Tracker: Reports and ExportsExport your transactions as CSV, PDF or a tax CSV.Expense Tracker: TransactionsAdd, search, export and import your transactions.Fraction CalculatorAdd, subtract, multiply and divide fractions with stepsFreelance Rate CalculatorWork out the hourly or project rate you actually need to charge as a freelancer to hit your target income.Fuel Cost CalculatorTrip fuel cost by distance, efficiency and priceGCD & LCM CalculatorGreatest common divisor and least common multipleGPA CalculatorCalculate your Grade Point Average from individual course grades and credit hours.Grade CalculatorCalculate your final course grade from weighted categories like homework, quizzes, exams and participation.Graphing CalculatorPlot any mathematical function instantly in your browser — polynomials, trigonometric functionsGrocery Price Comparison CalculatorWork out which size or brand is really cheaper per unitHabit TrackerTrack daily habits with a streak calendar, saved on your deviceHidden Cashflow AnalyzerFind the recurring costs quietly draining your monthly budget: forgotten subscriptions, small daily habitsHourly to Salary CalculatorConvert an hourly wage to weekly, monthly and yearly pay — before and after real taxesInflation CalculatorSee what an amount of money from any year since 1913 is worth today, using real US CPI dataInvestment CalculatorProject how an investment grows over time using compound interest, including optional regular contributions.Invoice GeneratorCreate and print a professional invoiceLive Cryptocurrency PricesLive prices, 24-hour and 7-day changes and a coin converter for the top cryptocurrenciesLive UV Index & Sun Safety CalculatorReal live UV index for your exact location right now, plus how many minutes until sunburn risk based on real forecast dataLoan EMI CalculatorWork out your Equated Monthly Instalment (EMI) for any personal, auto or business loan.Meeting Cost CalculatorSee the real running cost of a meeting, live, based on attendee count and pay rates — a real number, not an abstractionMeeting Time Planner Across Time ZonesFind a meeting time that works across several time zones at onceMercari Fee CalculatorReal Mercari selling fee and payment processing fee, auto-calculated into your true net payoutMonte Carlo Investment Risk SimulatorSee a range of possible outcomes for an investment with a Monte Carlo simulation.Mortgage CalculatorEstimate your monthly mortgage payment from the home price, down payment, interest rate and loan term.Moving Checklist GeneratorA room-by-room checklist and timeline for moving houseOven Temperature & Cooking ConverterConvert oven temperatures between Fahrenheit, Celsius and gas mark, with fan-oven adjustmentOvertime Pay CalculatorReal overtime pay at time-and-a-half or double-time, plus your total paycheck for the weekPaycheck Frequency Comparison CalculatorCompare your real take-home pay per check across weekly, biweekly, semimonthly and monthly payPayPal vs Stripe Fee CalculatorCompare real PayPal and Stripe payment processing fees side by side, plus reverse 'what to charge to net $X'Percentage CalculatorWork out any percentage problem instantly: what percentage one number is of another, what a percentage of aPhone Storage Calculator — How Many Photos &See how many photos or how many hours of video actually fit in your phone's storagePlanet Visibility TonightReal astronomical calculation of which naked-eye planets are above the horizon tonight from your exact locationPoshmark Fee CalculatorReal Poshmark seller fee and net payout, auto-calculated from Poshmark's real flat fee structurePregnancy Due Date CalculatorEstimate your due date and pregnancy weekPrime Number CheckerIs it prime? Factorise big numbers instantlyPrintable Calendar & Planner GeneratorGenerate a printable monthly or yearly calendar for any month and yearProfit Margin CalculatorMargin, markup, profit and break-evenQuadratic Equation SolverSolve ax²+bx+c=0 with steps, roots and vertexRandom Number GeneratorRandom numbers, dice rolls and coin flipsRandom Team & Group GeneratorSplit a list of names into random, balanced teams or groupsRecipe Unit Converter & ScalerConvert cups, grams and ounces, and scale a recipe up or downRent Affordability Calculator — How Much RentSee the real maximum rent you can safely afford from your income and actual expensesRent vs Buy CalculatorCompare the true cost of renting against buying a home over timeResistor Color Code CalculatorDecode a resistor's colour bands into its resistance value, or encode a value into bandsRunning Pace CalculatorPace, speed, finish times & race predictionsSalary CalculatorConvert your salary between annual, monthly, weekly, daily and hourly pay, and estimate your take-home paySavings Goal CalculatorHow long to reach your goal, or how much to saveScientific CalculatorA full scientific calculator in your browser, covering everything from basic arithmetic to trigonometryShopify Transaction Fee CalculatorReal Shopify payment processing rates by plan and payment method, auto-calculated into your net payoutShopping List & Budget TrackerA shopping list with a running total so you never go over budgetSleep CalculatorFind the best bedtime or wake-up timeStartup Cost Calculator — Itemized BusinessBuild your own itemized startup cost list and see your real total, category breakdown and runwayStatistics CalculatorMean, median, mode, standard deviation & moreStock AnalysisType a ticker such as AAPL, MSFT or NVDA and this tool builds a single 0-100 score from four partsTabata / HIIT Interval TimerA configurable work/rest interval timer with rounds, sound cues and a visual countdownTax CalculatorEstimate your federal income tax based on your income, filing status and standard deductions, using currentTime Zone ConverterConvert times between cities and time zonesTip CalculatorCalculate the tip and total bill for a restaurant check, and split it evenly between any number of people.Travel Packing List GeneratorBuild and check off a packing list for any tripTyping / Data Entry Job Earnings CalculatorA realistic monthly earnings estimate for typing, data-entry or transcription workUnit ConverterConvert between units instantly: length, weight, temperature, volume, area, speed, time, pressure, energy andUnit Price ComparatorCompare grocery and shopping prices by weight, volume or item to find the real best valueVAT / GST / Sales Tax CalculatorAdd or remove VAT, GST or sales taxWalmart Marketplace Fee CalculatorReal Walmart Marketplace referral fee by category, auto-calculated into your net payoutWeather ForecastCurrent weather, 24-hour chart and 7-day forecast for any city20-20-20 Eye Break TimerA screen-break timer that follows the 20-20-20 rule for eye strainAdd Watermark to PhotosStamp text or a logo watermark on your photos with opacity, rotation and tilingAir Quality Index by CityLive air quality, PM2.5 and pollutants for any city with health adviceAspect Ratio CalculatorFind a ratio and resize images or videos correctlyAudio Cutter & TrimmerCut, trim or remove parts of an audio file and download as WAVAudio Format ConverterConvert audio between WAV and MP3 in your browserAudio Pitch & Tempo ChangerChange an audio file's real pitch and tempo independently, using a real time-stretching algorithm, in your browserAudio Recording Quality CheckerReal DSP analysis of an uploaded audio file — detects clipping, silence, mono/stereo and dynamic range issuesBarcode GeneratorCreate Code 128, EAN-13, UPC-A, EAN-8 and Code 39 barcodes as PNG or SVGBase64 Encoder and DecoderEncode and decode Base64 for text and files.Battery Status CheckerSee your battery level, charging state and time remaining live in the browserBlue Light Filter & Screen DimmerAdd a warm-tone overlay and extra dimming to your screen for evening useBlur & Redact ImageHide faces, names, numbers and addresses in a screenshot or photo before you share itBrowser Feature & Codec Support TestSee which web features, video/audio codecs and image formats your browser supportsBrowser Privacy & Fingerprint TestSee exactly what websites can learn about your browser without askingBusiness Card MakerDesign and download a print-ready business cardChmod Permissions CalculatorLinux file permissions: octal, symbolic & commandsClick Speed TestHow many clicks per second can you do? Test 1 to 60 secondsCoin Flip, Dice Roller & Random PickerTrue-random coin flips, dice (d4–d100), yes/no decisions and a list pickerColor Blindness SimulatorSee any image as people with protanopia, deuteranopia or tritanopia see itColor Contrast CheckerCheck text and background contrast for accessibilityColor Converter & Contrast CheckerHEX, RGB, HSL converter with WCAG contrastColor Palette ExtractorPull the dominant colours out of any image as HEX, RGB and HSLColor-Blind-Safe Palette GeneratorGenerate a set of colors that stay visually distinct for protanopia, deuteranopia and tritanopia, not just for typical visionComputer Speed TestBenchmark your computer or phone in 10 seconds and compare devicesContract/PDF Redline Diff ViewerCompare two PDF, text or Word documents and see a redline of every changeCredit Card Number ValidatorCheck whether a card number passes the real Luhn checksum used by card networks, or generate test numbersCron Expression GeneratorBuild and explain cron schedules with next run timesCSS Box Shadow GeneratorDesign box shadows visually and copy the CSSCSS clamp Fluid Typography CalculatorGenerate a CSS clamp() value for font sizes that scale smoothly between viewportsCSS Flexbox Playground & GeneratorVisually build a flexbox layout and get the generated CSSCSS Gradient GeneratorCreate linear, radial and conic gradients with CSS codeCSS MinifierPaste your CSS or upload a .css file and shrink its size by stripping comments, collapsing unnecessaryCSV to SQL INSERT GeneratorConvert a real CSV file into real SQL INSERT statements, with automatic column type detection, ready to runCSV ⇄ JSON ConverterConvert CSV to JSON or JSON to CSV instantly in your browserData Format ConverterConvert CSV to JSON, XML to JSON, Base64 and URL encoding in one tool.Dead Pixel Test & Screen Checker11 full-screen colours, 15 test patterns, pixel fixer and an inspection reportDecibel MeterMeasure noise levels with your microphone — with A-weighting, min/max and alertsDiceware Passphrase GeneratorGenerate a long, truly random, memorable passphrase from real dice-equivalent word selectionDigital MagnifierUse your device's camera as a zoomable, high-contrast magnifying glassDisposable Email CheckerCheck whether an email address is from a known throwaway/temp-mail domain before you rely on itDomain Age & Expiry CheckerFind out when a domain was registered, when it expires and who the registrar isDuplicate File FinderFind exact duplicate files by comparing their content, not just the nameEmail Setup CheckerTest your domain's email authentication and get a score with fixesExact Time & Clock Accuracy CheckSee the exact time and how many milliseconds your device clock is offExcel/Sheets Formula ExplainerPaste an Excel or Google Sheets formula and get a real, step-by-step structural breakdown of exactly what it computesEXIF Viewer & Photo Metadata RemoverSee what a photo reveals — GPS location, camera, date — and remove it in one clickFavicon GeneratorTurn any logo into a complete favicon set — ICO, PNGs, manifest and HTML tagsFile Hash & Checksum VerifierCompute a file's real SHA-256, SHA-1 and MD5 checksum in your browser and compare it to an expected hashFlight Status TrackerLook up a flight number for times, terminal, gate and live position.Gamepad & Controller TesterTest every button, stick, trigger and vibration — and check for stick driftGIF Maker from ImagesTurn a series of photos into an animated GIFHandwriting Practice Sheet GeneratorCreate printable dotted-line handwriting practice sheets for any textHash GeneratorGenerate cryptographic hashes for text or files using MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512HTML Entity Encoder / DecoderEncode or decode &, <, © and moreHTML FormatterThis HTML formatter takes a snippet or a whole page and does one of three things: it beautifies the markupHTTP Status Code ReferenceSearch or browse every standard HTTP status code with its real meaning and common causesIBAN ValidatorCheck whether an IBAN is structurally valid and see its country, check digits and bank identifierImage CropperCrop, rotate and flip photos with aspect-ratio presets — download as PNG, JPG or WebPImage Format ConverterConvert images between PNG, JPG, WebP, BMP and GIF entirely in your browserImage Noise ReducerReduce real grain and sensor noise in a photo using an actual pixel-level denoising filter, right in your browserImage to Base64 ConverterTurn an image into a Base64 data URIImage Upscaler & SharpenerEnlarge a small image and sharpen the result using real multi-step resampling and an unsharp maskInstalled Font CheckerFind out which fonts are installed on your device and preview themInternet Speed TestMeasure download, upload, ping and jitter in about 30 secondsJavaScript Minifier & BeautifierStrip comments and excess whitespace from JavaScript, or re-indent minified code to read itJSON Formatter, Validator & BeautifierFormat, validate and minify JSON with clear error locationsJWT DecoderPaste any JSON Web Token and instantly see its decoded header, payload and signature, color-coded forKeyboard TesterDetects MacBook, Windows or phone, shows the right layout and tests every keyLive Aircraft Tracker Near YouSee real aircraft currently flying near your location right now, using live public ADS-B flight-tracking dataLive Earthquake TrackerSee recent earthquakes worldwide on a live map and list, straight from the USGSMAC Address Lookup & FormatterValidate a MAC address, reformat it, and look up its likely hardware vendor from its OUI prefixMarkdown Live Editor & PreviewerWrite Markdown on the left, see the rendered preview update live on the rightMarkdown to PDF ConverterPaste Markdown and download a clean, real-text PDF with headings, lists, bold, code blocks and tablesMeme GeneratorAdd classic top/bottom captions to any image and download your memeMicrophone TestCheck your mic level live, and record a 5-second test to hear yourselfMind Map & Outline BuilderBuild a nested outline and see it rendered as a visual mind mapMonitor Refresh Rate TestMeasure the real refresh rate and frame time of your screenMouse Tester & Polling Rate TestTest every button, the wheel, double-click faults and your mouse polling rateNumber Base ConverterBinary, octal, decimal, hex & any base 2–36Online Alarm ClockFree alarm clock with sounds, repeat days, snooze and quick timers — right in your browserOnline Metronome & Tap TempoA precise metronome with tap tempo, accents, time signatures and subdivisionsOnline RulerA real-size on-screen ruler you calibrate with a credit cardOnline Tone GeneratorGenerate sine, square, triangle and sawtooth tones at any frequency.Online TunerTune any instrument with your microphone — live pitch, note and centsOnline Voice RecorderRecord audio in your browser, pause, play back and download as WebM/M4A or WAVPaper Size Reference & ComparisonLook up exact A-series, B-series, Letter and Legal paper dimensions in mm, inches and pixels at any DPIPassword Breach CheckerFind out if your password appeared in a data breach — without sending itPassword GeneratorCreate strong, random passwordsPassword Strength & Crack-Time CheckerReal entropy-based analysis of a password's actual strength and an estimated real-world crack time, computed locallyPassword-Protected ZIP Creator & ExtractorCreate a real password-protected, AES-encrypted ZIP archive, or open one you have the password for — entirely in your browserPDF Form FillerFill in the real AcroForm fields of an uploaded PDF form and download the completed filePDF Page Numbers & Bates StamperAdd page numbers or sequential Bates numbers to a PDFPDF Page OrganizerDrag to reorder, rotate or delete PDF pages, then download the rebuilt filePDF Permanent Redaction ToolPermanently remove selected text and regions from a PDF by rebuilding it as a flattened image — not just a visual black boxPDF Splitter by Text MatchSplit a PDF into separate files automatically at every page containing a real text or regex match you specifyPDF to Images ConverterConvert every page of a PDF into a real, full-resolution PNG image and download them all as a ZIPPhoto Background BlurKeep a subject sharp and blur everything around it for a portrait-mode look, right in your browserPhoto Collage & Grid MakerArrange several photos into a grid or collage and download one imagePing TestMeasure your ping, jitter and packet loss to servers around the worldPPI / DPI CalculatorCalculate a screen's real pixel density (PPI) from its size and resolution, or the resolution needed to print at a target DPIPublic Holidays by CountrySee every public holiday for 100+ countries, find long weekends and export to your calendarQR Code & Barcode ScannerScan QR codes and barcodes with your camera or from an image — safelyQuick Sketch & WhiteboardA simple drawing canvas for quick sketches, diagrams and notes, exportable as an imageRegex Pattern Library & TesterA curated library of ready-made, real regex patterns for email, URL, phone, IPv4 and more — test any of them instantlyRegex Tester with Live Match HighlightingTest regular expressions with live highlighted matches and capture groupsScreen Color PickerPick the exact color of any pixel on your screen — any app, any window — using your browser's native eyedropperScreen Recorder & ScreenshotRecord your screen, a window or a tab with audio — no install, no watermarkSecret Note Link GeneratorEncrypt a note with a password and share it as a single link — nothing is stored on a serverShoe & Clothing Size ConverterConvert shoe and clothing sizes between US, UK, EU and CM using real published size chartsSignature GeneratorType your name and get a cursive signature image to downloadSpeaker & Headphone TestCheck left and right channels, balance and wiring on any speakers or headphonesSSL Certificate Batch CheckerCheck the real SSL/TLS certificate expiry, issuer and trust status of up to 20 domains at once, side by sideStorage Unit ConverterConvert bytes, bits, KB, MB, GB, TB and PB, showing both binary (1024-based) and decimal (1000-based) valuesSubnet / CIDR CalculatorEnter an IP and CIDR prefix to get network address, broadcast address, usable range and host countSubtitle Editor & GeneratorEdit, retime and export SRT/VTT subtitles, or auto-generate them from audio/videoSunrise, Sunset & Moon Phase CalculatorSunrise, sunset, twilight, golden hour and moon phase for any place and dateSVG Optimizer & MinifierShrink SVG file size by removing metadata, comments and excess precisionSVG to PNG / JPG ConverterConvert an SVG vector image to a PNG or JPG raster image at any pixel sizeTelegram & WhatsApp Group AnalyzerCheck a public Telegram or WhatsApp group before you join it.Temp Mail — Free Disposable Email AddressGet a free temporary email address in one click and read incoming mail instantlyTouch Screen TestCheck multi-touch, draw with your fingers and find dead zones on any touch screenUnix Timestamp ConverterConvert Unix time to dates and backUPC / Barcode Product LookupScan or type a real UPC/barcode number and look up real product information from a live public product databaseURL Encoder and DecoderPercent-encode and decode URLs and text.UUID GeneratorGenerate v4 UUIDs / GUIDs in bulkVideo Frame GrabberCapture any frame from a video as PNG, JPG or WebP — frame by frameVideo to GIF ConverterConvert a real video clip into an animated GIF with real frame-rate, size and trim-range controls, entirely in your browserVideo Watermark ToolStamp a real text or logo watermark onto every frame of a video and export a genuinely watermarked video fileVoice TypingDictate live and see your words typed out as you speak, using your microphoneWebcam TestTest your camera online — see the live picture, resolution and frame rateWebRTC Leak TestCheck whether your browser leaks your real IP address through WebRTCWebsite Favicon MakerGenerate a full favicon set from one image, in every size a browser needsWhat Is My Screen Resolution & Device InfoSee your screen resolution, window size, pixel ratio, browser, OS and GPUWhere Am I? IP & Location CheckerSee your public IP address, approximate geographic location (city, region, country), internet serviceWhich File Format Should I Use?Answer a few real questions and get an accurate, technically-grounded file format recommendation with the real tradeoffsWhite Noise & Focus Sound GeneratorPlay white, pink or brown noise and other focus/sleep sounds in your browserYouTube Thumbnail DownloaderGet every available resolution of a YouTube video's thumbnail, instantlyZIP Creator & ExtractorCreate ZIP files or open and extract them right in your browserAnchor Text Ratio AnalyzerEnter a URL and this tool crawls the page, collects every anchor text used in the links it finds, andContent Cannibalization CheckerEnter a domain and a target keyword, and this tool crawls the site (up to 50 pages), scores every page itCrawl Depth CheckerEnter a domain and this tool crawls it (up to 100 pages) while tracking exactly how many clicks each page isDNS LookupLook up A, AAAA, MX, NS, TXT, CNAME, SOA and CAA records for any domainDNS Propagation CheckerSee if a DNS change has spread by comparing Google and Cloudflare's global resolvers side by sideGoogle Indexation CheckerPaste up to 100 URLs and this tool checks each one live to confirm whether it's actually accessible —Internal Link FinderEnter a starting URL and this tool crawls the site (up to 100 pages), extracts keywords from every page'sIs Website Down? Website Status CheckerCheck if a website is up, its response time, IP and security headersKeyword CPC CalculatorEnter your total ad spend and total clicks for a campaign or keyword, and this tool instantly calculates yourKeyword Research ToolEnter a seed keyword and this tool pulls real, live keyword ideas from Google and Bing's own autocompleteMeta Tag GeneratorGenerate SEO, Open Graph and Twitter meta tagsReadability Score CheckerFlesch reading ease & grade level for any textRedirect Chain VisualizerEnter a URL and this tool follows every redirect it produces, hop by hop, up to 10 redirects deep, showingRobots.txt & Sitemap.xml ValidatorCheck robots.txt syntax and sitemap.xml structure for errors that block GoogleRobots.txt GeneratorCreate a robots.txt file for your websiteSEO AnalyzerEnter a starting URL and this tool crawls up to 40 pages of that site (following internal links, 8-secondSERP Title Pixel Width CheckerType in a title tag and this tool measures its actual rendered pixel width using the same Arial-basedSitemap vs Crawl ComparisonEnter a site's URL and this tool pulls the real URLs listed in its XML sitemap, separately crawls the liveSocial Share Preview SimulatorSee how your link looks on Facebook, X, LinkedIn and Google before you share itSSL Certificate CheckerCheck a domain's SSL/TLS certificate, expiry date, issuer and trust statusTech Stack DetectorEnter any public URL and this tool fetches the live page and its response headers, then scans for realThin Content DetectorEnter a domain and this tool crawls it (up to 100 pages), counts the real word count of each page's contentURL Slug GeneratorTurn titles into clean SEO-friendly slugsUTM Link BuilderBuild tagged campaign URLs for Google AnalyticsWebsite Speed TestEnter any URL and this tool fetches it live, timing the full response, measuring Time to First Byte (TTFB)Word Frequency CounterCount repeated words and keyword densityXML Sitemap GeneratorPaste a list of URLs and generate a valid sitemap.xml with lastmod, changefreq and priorityCitation GeneratorA good citation gives credit to your sources and protects you from plagiarism.Dilution CalculatorSolve C1V1 = C2V2 for the value you are missing.DNA Sequence AnalyzerPaste any raw DNA sequence — from GenBank, Ensembl, NCBI, a FASTA file, or your own lab data — and run sixFlashcard MakerFlashcards are one of the most effective ways to learn because they force active recall: you try to rememberHomework PlannerA homework planner turns a messy pile of assignments into a clear, prioritised to-do list.Ideal Gas Law CalculatorSolve PV = nRT for pressure, volume, moles or temperature.Legal Cases LibraryWorld Law's Cases library is a searchable, filterable collection of legal cases from courts around the worldMolar Mass CalculatorFind the molar mass of any chemical formula.Mole CalculatorMoleMath helps you solve the mole problems that appear in every chemistry course: converting between gramsMolecule ViewerChemScope lets you draw 2D chemical structures, view molecules in 3D and look up more than 900 compounds.Periodic TableA fully interactive periodic table with search-as-you-type (by element name, symbol or atomic number withpH CalculatorpH for strong and weak acids and bases, buffers and Henderson-Hasselbalch.Solution Concentration CalculatorWork out molarity, molality and other concentration units.Study TimerA focus timer built around a large digit-style countdown you can adjust directly (click the up/down controlsWorld Law ComparisonWorld Law's Compare tool puts any two laws from the library side-by-side and uses AI to generate aWorld Law LibraryBrowse laws of every country in one library.World Law TimelineThe World Law Timeline lays out every law in the library chronologically by the decade it was enacted, fromAmharic KeyboardAZRS's online Amharic keyboard lets you type Ethiopic (Ge'ez) script in any browser.Arabic KeyboardAZRS's online Arabic keyboard lets you type Arabic script directly in your browser — no software, no browserArmenian KeyboardAZRS's online Armenian keyboard lets you type the Armenian alphabet in any browser.Bengali KeyboardAZRS's online Bengali keyboard lets you type Bangla script in any browser without software installs.Burmese KeyboardType in Burmese (Myanmar) online.Chinese KeyboardAZRS's online Chinese keyboard lets you type Simplified Chinese characters in any browser without installingCzech KeyboardType in Czech online.French KeyboardType in French online.Georgian KeyboardAZRS's online Georgian keyboard lets you type the unique Mkhedruli script in any browser.German KeyboardType in German online.Greek KeyboardAZRS's online Greek keyboard lets you type modern Greek and ancient Greek characters in any browser.Gujarati KeyboardType in Gujarati online.Hausa KeyboardType in Hausa online.Hebrew KeyboardAZRS's online Hebrew keyboard lets you type modern Hebrew and biblical Hebrew (with nikud vowel marks)Hindi KeyboardAZRS's online Hindi keyboard lets you type Devanagari script in any browser.Indonesian KeyboardType in Indonesian online.Italian KeyboardType in Italian online.Japanese KeyboardAZRS's online Japanese keyboard lets you type Hiragana and Katakana scripts in any browser without installingKannada KeyboardType in Kannada online.Kazakh KeyboardType in Kazakh online.Korean KeyboardAZRS's online Korean keyboard lets you type Hangul script in any browser without installing a Korean IME orMalayalam KeyboardType in Malayalam online.Mongolian KeyboardType in Mongolian online.Nepali KeyboardType in Nepali online.Persian KeyboardAZRS's online Persian keyboard lets you type Farsi script in any browser on any device.Polish KeyboardType in Polish online.Portuguese KeyboardType in Portuguese online.Punjabi KeyboardType in Punjabi online.Russian KeyboardAZRS's online Russian keyboard lets you type Cyrillic script in any browser without changing system settings.Sinhala KeyboardType in Sinhala online.Somali KeyboardType in Somali online.Spanish KeyboardType in Spanish online.Swahili KeyboardType in Swahili online.Tamil KeyboardType in Tamil online.Telugu KeyboardType in Telugu online.Thai KeyboardAZRS's online Thai keyboard lets you type Thai script with tone marks and vowels in any browser.Tibetan KeyboardType in Tibetan online.Turkish KeyboardAZRS's online Turkish keyboard lets you type Turkish text with all special characters — ğ, ş, ı, İ, ö, ü, ç —Ukrainian KeyboardType in Ukrainian online.Urdu KeyboardAZRS's online Urdu keyboard lets you type Urdu Nastaliq script directly in your browser without any softwareVietnamese KeyboardType in Vietnamese online.Virtual KeyboardAZRS's virtual keyboard hub lets you type in Arabic, Urdu, Hindi, Persian, Hebrew, Russian, ChineseYoruba KeyboardType in Yoruba online.3D Model to GIF, PNG & Video Preview MakerTurn an STL, OBJ, 3MF or STEP file into a transparent PNG, turntable GIF or video3D Model Viewer & AnalyzerView any 3D model, measure it and check it's print-ready3D Print Cost CalculatorCost per print with quantity pricing, currency, G-code/STL import and a cost-split chart3D Print Orientation OptimizerFind the best print orientation for less support, speed, strength or surface3D Printer Calibration G-code GeneratorGenerate temperature tower, retraction, flow, max-flow, pressure advance & bed-level G-code3MF ⇄ STL ConverterConvert 3MF to STL and STL to 3MF, including multi-object slicer filesAdd Text, Logo or Base Plate to an STLEmboss or engrave text and SVG logos on any face of an STL, or add a flat base plateCAD Unit & Drawing Scale Converter16 units at once, drawing scales (incl. architectural), paper-fit scale and scale finderDrawing Sheet Border & Title Block GeneratorCreate ISO or ANSI drawing sheets with border, zone references and a filled-in title block as SVG or DXFDXF to STL Extruder — 3D Print from a DXFExtrude closed outlines in a DXF into a watertight STL with holes, scale and optional base plateDXF ⇄ SVG ConverterConvert DXF to SVG and SVG to DXF for laser cutters, CNC and CADEngineering Drawing Checklist — Title BlockInteractive checklist to catch missing items before you submit a CAD drawingFilament Weight ⇄ Length ConverterGrams, metres and cm³ for 16 materials, spool remaining, job check and cost per metreG-code Editor & Inspector — Insert PausesInsert filament changes, pauses, temperature/speed changes at a layer; strip & compressG-code Print Time & Filament Cost EstimatorAccurate print time with acceleration, plus filament, power and business costG-code to SVG / PNG / DXF Toolpath ConverterExport G-code toolpaths as SVG, PNG or DXF, per layer or flattenedG-code Viewer & Print Time Estimator3D + 2D G-code preview by feature, speed and layer, with time and flow statsHeat-Set Insert, Screw Hole & 3D-PrintHole sizes for heat-set inserts, screws and press fits by printer typeImage to SVG / DXF Vector Tracer for Laser &Trace a picture into clean vector outlines (SVG or DXF) with threshold, smoothing and specks removalIsometric, Dot & Graph Grid Paper GeneratorMake printable isometric, dot, graph, hex and engineering grid paper in any size and spacing as SVG or 300 dpi PNGLaser & CNC Nesting Tool — Pack Parts ontoPack the parts in a DXF or SVG onto sheets of your size with quantities, spacing and rotationLaser Cutter SVG & DXF CleanerFix messy cutting files: join loose lines, remove double cuts, close gaps and order cuts inside-outLayer Height & Nozzle Settings CalculatorLayer height, line width, walls, first layer, speed limits and Z-step-friendly layer heightsOnline DXF Viewer with Measure Tool, Layers &View a DXF file in your browser: zoom, pan, toggle layers, measure with snapping and see shape propertiesOnline STL Slicer Preview — Layers, PrintSlice an STL into layers, scrub through them and estimate time, filament and costOnshape Export Format Helper — Which FormatPick the right Onshape export format and settings for printing, laser, CAM, AR, sharingOnshape FeatureScript Snippet Library & CheatCopy-paste FeatureScript snippets: parameters, sketches, booleans, patterns, queriesOnshape Sketch Constraints, Shortcuts &Understand sketch constraints, fix over-defined sketches, and learn good Onshape habitsOnshape to Slicer 3D Printing Workflow GuideStep-by-step Onshape → STL → slicer checklist for Orca, Bambu, Prusa and CuraPDF Drawing to DXF / SVG Vector ExtractorExtract the real vector lines and curves from a PDF drawing into DXF or SVG at true scalePLY / OFF / AMF / GLB / FBX / 3DS to STLConvert PLY, OFF, AMF, GLB, glTF, FBX and 3DS files to STL for printingResin 3D Print Calculator — Exposure, Time &Print time, resin volume & cost, exposure time from cure curve, pixel sizeSTEP / IGES to OBJ & GLB ConverterCAD solids to OBJ or GLB for AR, web 3D, Blender and UnitySTEP / STP to STL ConverterConvert STEP, STP & IGES CAD files to STL, OBJ, 3MF — free, in your browserSTL Boolean ToolMerge, cut or intersect two 3D models, or drill holes with built-in primitivesSTL Cross-Section to DXF / SVG OutlineCut a 3D model with a plane and export the section outline, area and perimeter, or all layers for laser-cut stacksSTL Hollow Tool — Hollow Out Models & SaveHollow an STL with a set wall thickness and a drain hole, see resin savedSTL Merge, Split & Cut ToolMerge STLs onto one plate, split shells apart, or cut a model with a planeSTL Overhang & Support CheckerSee which faces need supports at your slicer's overhang angleSTL Repair Tool & Mesh CheckerFind and fix holes, flipped normals and non-manifold edges in STL filesSTL Scale, Rotate, Mirror & Unit Fix ToolFix 'model is 25.4× too big', rotate, mirror and resize STL filesSTL Simplifier & SmootherReduce the triangle count of a heavy STL/OBJ or smooth a rough scan without shrinking itSTL to 2D Drawing — Top, Front & Side ViewsTurn a 3D model into a third-angle three-view outline sheet with overall dimensions, as SVG or DXFSTL to STEP ConverterTurn an STL mesh into a STEP B-rep solid with planar facesSTL Wall Thickness CheckerFind walls that are too thin to print and see them highlighted in red on the modelSTL Weight, Centre of Mass & Moment ofExact volume, mass, centre of gravity and inertia tensor of any STL, OBJ, 3MF or STEP modelSTL ⇄ OBJ 3D Model ConverterConvert STL, OBJ, PLY, 3MF, AMF, GLB — batch, with unit fixSVG / DXF Path Offset & Kerf Compensation ToolGrow, shrink or kerf-compensate every closed path in an SVG or DXF so laser and CNC parts finish at the drawn sizeSVG to DXF Converter with Unit & Scale ControlExact-size SVG to DXF: pick source units, scale to a width, layers by colour2D Truss Solver — Member Forces, Reactions &Solve pin-jointed trusses: tension/compression in every member, support reactions and displacements, with a force diagramBeam Deflection & Stress CalculatorDeflection, reactions, bending moment and stress for supported and cantilever beamsBolt Circle & Hole Pattern CoordinateHole coordinates for bolt circles, rows and grids with DXF, SVG and G-code exportBolt Torque, Preload & Strength CalculatorTightening torque, clamp force, proof load and design resistances for M3–M36 bolts by property classCNC Machining Cost & Time EstimatorEstimate CNC milling time, cost per part and price vs quantityComposite Section Moment of Inertia CalculatorCentroid, moment of inertia and section modulus of any shape built from rectangles, circles, triangles, semicircles and holesCompression Spring Design CalculatorSpring rate, stress, solid height, buckling and number of coils for compression springsEngineering Unit Converter with UnitConvert any engineering unit or compound expression (lbf*ft to N*m, psi to MPa, kg*m/s^2 to N) with dimension checkingFeet & Inches CalculatorConstruction calculator for feet-inch-fraction arithmetic and dividing a length into equal spacesFillet Weld Size & Strength CalculatorCapacity of fillet welds from leg size and length: AISC ASD/LRFD and Eurocode 3, with minimum and maximum sizeGD&T Symbols Reference & Feature ControlLearn the 14 GD&T symbols, tolerance zones and modifiers, and build a feature control frame to copy or downloadGear Calculator & Involute Gear SVG/DXF/STLModule, pitch, centre distance, ratio — and export gears as SVG, DXF or STLHeat Sink & Thermal Resistance CalculatorRequired heat-sink thermal resistance, finned heat-sink estimate, interface conduction and regulator heatISO 286 Fit & Tolerance CalculatorLimits and fits for any size: hole/shaft deviations, clearance or interferenceKeyway & Parallel Key Size Chart and TorqueLook up key width, height and keyway depths for any shaft diameter and check the torque capacityLaser Cutting Cost & Time EstimatorUpload SVG/DXF to measure cut length and pierces; get time, material and priceMaterial Weight CalculatorWeight from dimensions and density for plates, bars, tubes, pipes and moremm ⇄ Inch Fraction & Tolerance ConverterMillimetres to inch fractions with tolerance limits and a batch listMohr's Circle Calculator — Principal StressesPrincipal stresses, maximum shear, von Mises and Tresca from σx, σy and τxy, with the circle drawnO-Ring Groove & Gland Design CalculatorSize an O-ring groove: gland depth, width, squeeze, fill and stretch for static, radial and dynamic sealsPipe Flow & Pressure Drop CalculatorVelocity, Reynolds number, friction factor, head loss, pressure drop and pump power for pipe flowSecond Moment of Area & Section PropertiesArea, centroid, Ix, Iy, section modulus, radius of gyration for common sectionsSheet Metal Bend Allowance & K-FactorBend allowance, bend deduction, setback, flat length and K-factor from a test bendSurface Finish Converter & ChartConvert Ra, µin, RMS and ISO N grades, with typical roughness by process and by applicationThread & Fastener Chart — Tap DrillMetric & imperial thread data: tap drill, clearance holes, head sizes, torqueTolerance Stack-Up Calculator1D tolerance stack-up with worst-case, RSS, Monte-Carlo simulation, contributors and out-of-spec prediction3D Print Tolerance & Clearance Test GeneratorGenerate a numbered test plate with holes of increasing clearance and matching pegs to dial in your printer's fit3D Print Troubleshooting Guide — FixPick a symptom and get the likely causes and exact fixes, ranked from most to least likely3D Printable Gear Generator — Spur, Helical &Generate true involute spur, helical and herringbone gears with bore, keyway, hub and a meshing partner as STL3D Text & QR Code STL GeneratorMake 3D text signs, keychains and scannable QR code plates as STL3D-Printable Box with Lid GeneratorParametric box and friction-fit lid STL with rounded corners and clearance3D-Printable Screw Thread GeneratorGenerate metric (ISO) and trapezoidal threads: bolts, nuts and threaded rods as watertight STLArduino, ESP32, Pico & ESP8266 PinoutSearchable pin functions, PWM/ADC/I²C/SPI pins and boot-strapping warnings for popular boardsBearing, Magnet & Nut Pocket Size CalculatorPocket and hole sizes for bearings, magnets, nuts and screw heads by printer and fit, with a test couponExtruder E-Steps, Rotation Distance & FlowCalculate new e-steps, Klipper rotation_distance, flow multiplier and maximum print speed from simple measurementsFilament Chooser — PLA vs PETG vs ABS vs ASATell it what the part needs and see the best-matching 3D printing materials with settings and trade-offsGridfinity Bin & Baseplate GeneratorGenerate custom Gridfinity bins and baseplates as STL — any size, dividers, scoopGyroid Lattice GeneratorGenerate printable gyroid, Schwarz-P and diamond lattice blocks with adjustable cell size and densityHeightmap / Image to STL Relief GeneratorConvert a grayscale image or terrain heightmap into a 3D-printable relief STLKeychain & Name Tag STL MakerCustom keychains and name tags with raised or inlay text, border and key-ring tab — STL / 3MFKnob & Thumb Screw Generator STLDesign fluted, knurled or lobed knobs with round, D-shaft or screw hole with hex nut trapLaser Cut Box GeneratorFinger-joint box and tray plans as SVG/DXF, with kerf and a living-hinge panelLaser Power/Speed Test Grid, Kerf Test &Generate GRBL G-code test grids, kerf/fit test files and read which materials are safe to laserLithophane Generator — Photo to 3D PrintableTurn a photo into a 3D-printable lithophane STL with backlit previewMouse Ears Generator — Anti-Warp Pads for STLAdd thin disc pads to the corners of a model to stop warping, without a messy brimParametric Bracket, Standoff & SpacerGenerate L-brackets, standoffs, spacers, washers and mounting plates as STLPCB Trace Width, Via Current & MicrostripIPC-2221 trace width and current, via capacity, resistance, voltage drop and microstrip impedancePegboard Panel & Peg Hook GeneratorPrint your own pegboard panels and two-peg hooks to custom sizesPrimitive Shapes STL Generator — CubeCreate exact test shapes — boxes, cylinders, tubes, spheres, tori, pyramids, wedges and more — as STLPrint-in-Place Hinge Generator & Snap-FitGenerate a working print-in-place hinge STL and calculate snap-fit cantilever deflection and forceStepper Steps per mm, Belt Length & PulleySteps per mm for belts and lead screws, belt length and centre distance, speed and torqueSVG to STL ExtruderExtrude SVG shapes into a printable STL with holes, base plate and keyring option10-Minute Abs WorkoutCore, lower abs and standing abs workouts with a 3D coach12-Week Workout ProgramsThree full 12-week programs with automatic progression and deload weeks7-Day & 30-Day Fitness Challenge TrackerPush-up, squat, plank and more: daily targets, calendar and streak7-Minute WorkoutThe classic 12-exercise 7-minute workout with a 3D coach and voiceAMRAP & EMOM Workout TimerAMRAP, EMOM and For Time with voice, round counter and movementsArm Workout No EquipmentTriceps, biceps and shoulders at home with a 3D coachBack Workout at HomeBodyweight, dumbbell and band back workouts with a 3D coachBarbell Plate CalculatorWhich plates to load on each side, with a visual barBasketball Shot CounterCounts your shooting motions and checks your follow-throughBeginner Workout PlansSix step-by-step plans: full body, push-ups, squats, core, 5K and mobilityBiceps Curl CounterCounts every biceps curl with your camera and tells you to curl higherBoxing & MMA Round TimerRounds with bell, 10-second warning clap and voice, presets for boxing and MMABoxing Punch CounterCounts every jab, cross and hook with your cameraCalories Burned CalculatorCalories burned by 37 activities, using MET values and your weightCamera Burpee CounterCounts burpees when you drop to the floor and stand back upCamera High Knees & Mountain Climber CounterCounts high knees or mountain climbers with the cameraCamera Jump Rope CounterCounts your jumps with the camera, with or without a ropeCamera Jumping Jack CounterCounts jumping jacks with your camera and says each numberCamera Lunge CounterCounts lunges with the camera and checks your front kneeCamera Pull-Up CounterCounts pull-ups when your chin clears the bar, any camera angleCamera Push-Up CounterYour camera counts every push-up and checks your form, from any angleCamera Sit-Up & Crunch CounterCounts sit-ups or crunches with your camera, from any angleCamera Squat CounterCounts your squats with the camera and checks depth, any angleCamera Workout ModeChain squats, push-ups, planks and more: the camera counts and the voice coachesChest & Shoulder Workout at HomePush-up variations and dumbbell presses with a 3D coachCricket Batting & Bowling AnalyzerBatting and bowling actions: arm speed, elbow, front knee, head stabilityCustom Workout Builder with Voice CoachChoose from 120+ exercises, set reps & sets, then follow the voiceCycling Calculators: Speed, Power, Gears & FTPSpeed/time/distance, watts needed, gear ratio and FTP zones in one pageDeload & Recovery Readiness AdvisorDaily readiness score: train hard, go light, rest or deloadDesk Exercise Reminder for Office WorkersMovement break reminders with 1-5 minute voice-guided desk routinesDesk Posture CheckerWebcam watches your posture and reminds you to sit up and stretchDiet & Meal Planner with Shopping ListCalorie-matched meal plans with macros and a shopping listDOTS & Wilks CalculatorPowerlifting score from squat, bench, deadlift and body weightDumbbell Full Body WorkoutFull body, upper body and lower body dumbbell workoutsDynamic Warm-Up Routine5-minute warm-ups for any workout, legs or upper bodyExercise Library with Animations170 exercises with animated demos, muscles and how-to cuesExercise Timer with VoiceType your exercises, set work and rest, and a voice calls each one outFFMI CalculatorLean mass, fat mass and FFMI with a muscularity ratingFitness Blog & Guides9 practical fitness guides: push-ups, reps, protein, stretching and moreFitness Test ScorecardRate your fitness by age and sex: push-ups, sit-ups, plank and 1.5-mile runFitness Tools HubFind the right fitness tool by goal: lose fat, get stronger, stretch, trackFood Calorie & Macro Lookup + Daily Diary150+ foods with calories, protein, carbs, fat and a daily food diaryGentle Rehab Routines: Back, Knee, Shoulder &Voice-guided gentle routines with 3D demos and clear safety notesGlute Bridge CounterCounts every glute bridge and prompts you to lift higherGlute Workout at HomeBridges, kicks and thrusts with a 3D demo and voice coachGolf Swing AnalyzerRecord or load a swing: tempo, rotation, head movement, compare two swingsGPS Run Tracker with MapTrack runs, walks and rides: distance, pace, splits, route map, GPX exportHeart Rate Zones CalculatorFind your 5 training zones and max heart rate by ageHip Hinge & Deadlift CounterCounts deadlifts, good mornings and hip hingesIdeal Weight CalculatorDevine, Robinson, Miller & Hamwi formulas plus a healthy BMI rangeInteractive Muscle MapTap a muscle to see what it does and the best exercises for itKick CounterCounts front, side and roundhouse kicks with your cameraKids PE Challenges & Class ScoreboardAnimal workouts, brain breaks and 60-second challenges with a scoreboardLateral & Front Raise CounterCounts every lateral or front raise to shoulder heightLeft-Right Balance & Symmetry TestCompare your left and right side: balance, squat, shoulders, push-upsLeg Day at HomeQuads, hamstrings, glutes and calves with a 3D coachLeg Raise CounterCounts lying leg raises and checks you lift toward verticalMacro CalculatorDaily calories and protein, carb and fat grams for your goalMeditation Timer with Guided Breathing & Bells3-30 minute sessions: guided breathing, body scan or silent with bells and ambient soundsMobility Screening TestDeep squat, toe touch, overhead reach and lunge, scored 0-3Morning Energy Workout5 or 10 minute wake-up workouts, including a no-jumping optionOne-Rep Max CalculatorEstimate your max lift from any set, with a training-weights tablePace Band & Split CalculatorPrintable splits for any race: even, negative or fast-start strategyPedometer for Your PhoneCounts steps with your phone's motion sensors, with distance and caloriesPersonal Records BoardAll your best lifts, rep records and run times in one placePlank Timer with Form CheckTimes your plank and warns you when your hips sag or liftProgress Photos with Before/After SliderPrivate photo timeline with a drag-to-compare before and after sliderPronunciation PracticeHear a model voice, say it yourself and get a word-by-word scoreProtein Intake CalculatorHow many grams of protein you need per day and per mealPush-Up Coach with VoicePick reps, sets & speed, then a voice says Down, Up, 1, 2, 3Quiet Cardio WorkoutApartment-friendly, low-impact cardio with a 3D coachRace Time Predictor & Training PacesPredict 5K to marathon times and get easy, tempo and interval pacesRep & Set TrackerLog weight, reps and sets, with an automatic rest timerRest Timer with VoiceRest timer between sets with voice alerts and auto-restartRun/Walk Interval Timer & Couch to 5KVoice-guided run/walk intervals: Couch to 5K, custom and speed playRunning Cadence & Music BPM CalculatorSteps per minute for your pace, and the pace for a song's BPMSenior Chair Exercises & Balance TestsChair workouts for older adults plus 30-second chair stand and balance testsShoulder Press CounterCounts every overhead press and checks you lock outSteps to Distance CalculatorConvert steps to km/miles, time and calories (and back)Strength Program CalculatorWeights for popular strength programs from your 1RMStrength Standards CalculatorHow strong are you? Bench, squat, deadlift levels by body weightStrength Workout for RunnersSingle-leg strength, glutes and core to run strongerStretch Routine Guide8 guided stretching routines with timers, sides and breathing cuesStretching Guides with Animations18 stretches with animated demos, steps, benefits and hold timesSweat Rate CalculatorHow much you sweat per hour and how much to drinkSwimming Calculators: Pace, Laps, Calories &Pace per 100 m, lap converter, calories burned and critical swim speedTennis Stroke AnalyzerForehand, backhand and serve: speed, rotation, knee bend, compare strokesText Reader with Highlighted WordsRead any text aloud and follow the highlighted wordTriceps Dip CounterCounts chair or bar dips from any angleVO2 Max CalculatorCooper, 1.5-mile, Rockport walk and resting heart rate methodsVoice CounterA voice counts out loud for you: up, down, by 2s, 5s or 10sWaist-to-Height & Waist-to-Hip RatioHealth-risk ratios from your waist, hip and heightWall Sit TimerTimes your wall sit and warns when you slide up or too lowWarm-Up Sets CalculatorRamp-up sets to your working weight, rounded to platesWeekly Workout PlannerChoose your days, goal and equipment, get a full week of workoutsWeight & Body Measurements TrackerTrack weight, waist, chest, hips, arms with charts and a goal lineWeight Loss Timeline CalculatorHow long to reach your goal weight, with a date and weekly projectionWorkout GeneratorPick muscles, equipment and minutes, get a full workout with animationsWorkout Log & History TrackerStreaks, a 20-week heat map and a log of every workoutYoga Flow BuilderBuild your own yoga flow from 50+ poses and let a voice guide youYoga Pose CheckerCamera checks your yoga pose joint by joint and tells you what to fixBrain Type Quiz — Fast Thinker, OverthinkerA short quiz that reveals your brain type with a shareable personality cardBroke Score — How Broke Are You Really?A funny but real 0-100% broke score from your income, spending and savingsCategory Rush GameName something in the category with a random letterClean Jokes TellerThousands of clean jokes with a punchline revealCompare Yourself to the WorldSee your estimated income and sleep percentile vs the world, based on cited averagesDigital Life Report — Brain Performance ScoreIn-page typing and reaction tests plus your habits, combined into one Brain Performance ScoreFive in a RowGomoku vs computer or a friend on one screenFocus Score Test — Real Timed Attention TestA real in-browser go/no-go attention test with a measured, timed scoreFuture Net Worth Simulator — Spend vs InvestCompare two real compound-interest projections: keep spending vs start investingGirls' Night Party GamesMost likely to... and Spill the Beans promptsGroup Story BuilderBuild a silly story one sentence at a timeHousie Tambola Number CallerNumber caller and ticket generator for HousieHow Well Do You Know Me?Friend and bride/groom quiz questionsLife in Numbers — How Much of Your LifeSee how many years you've spent asleep and on your phone, from your own numbersMafia Role DealerDeal secret Mafia roles and read the narrator scriptMancalaClassic Mancala vs computer or two playersMove-Out Readiness ScoreA real 50/30/20-style affordability score for moving out on your ownNever Have I Ever Questions1,200+ clean Never Have I Ever promptsOne Sentence About Your LifeA few quick picks generate one blunt, reflective sentence about where you're atOverthinking Score — Rumination Self-CheckA short self-report quiz based on real rumination-scale concepts, with a percentile scoreParty Bingo CardsBridal, baby shower, mehndi, birthday and girls' night bingoPass the Bomb GameHidden-timer party game: name one and pass it onPictionary Word GeneratorEasy, medium and hard drawing words with a timerRapid Fire Questions10 quick questions, 5 seconds eachRarity Score — How Rare Are You?An 8-question quiz that reveals how rare your everyday habits really areRiddles with AnswersBrain-teasing riddles, answer hidden until you tapRideshare Driver Profit Reality CheckReal effective hourly take-home after true vehicle costs, vs local minimum wageSilly Would You RatherAbsurd dilemmas with a group vote counterSleep Debt Calculator — Real Nights OwedReal arithmetic on how many full nights of sleep you're behind onSmarter Than Average QuizA 6-question logic trick-quiz with a percentile score vs a stated averageSticks GameTake 1 to 3 sticks; last stick losesSubscription Cost Reality CheckAdd your subscriptions and see the real annual total plus relatable comparisonsTeam Trivia BattleTeam quiz night with 4,600+ questionsText Personality AnalyzerPaste your own text for a heuristic style read — confident but impatient? Curious and detailed?Time Wasted on Phone — Lifetime CalculatorReal arithmetic on how many years of your life you'll spend on your phoneTongue Twister Challenge200+ tongue twisters to say three times fastTruth or Dare GeneratorClean truth and dare prompts, no repeatsTwo Truths and a LieTopic prompts and a score of who fooled the groupUndercover Word GameSpy word party game, pass one phone aroundWheel of NamesAdd names, spin the wheel and pick a fair random winner.Where Should You Live? Personality ArchetypeA fun quiz matching your preferences to a place archetype — not real relocation adviceWho Am I? Guessing GameHeads-up charades with a timer, 400 wordsWould You Rather Questions4,500 would-you-rather dilemmas3-Way Loan Comparison ToolCompare up to three real loan offers side by side — payment, total interest, and total cost — so you can see instantly which offer actually wins.401 CalculatorProject your 401(k) balance including employer match.529 College Savings Plan CalculatorProject tax-advantaged 529 plan growth toward a future college cost goal.Amortization CalculatorSee exactly how each payment splits between principal and interest over the life of your loan.Annuity CalculatorProject the future value of a stream of regular payments.Annuity Payout CalculatorConvert a lump sum into a guaranteed monthly payout.APR CalculatorSee the true annual cost of a loan once lender fees are blended in.Area ConverterFree area converter for square metres, square feet, acres and hectares.Auto Lease CalculatorEstimate your monthly lease payment using the money factor method.Auto Loan CalculatorCalculate your monthly car payment including trade-in and sales tax.Average Return CalculatorCalculate the compound annual growth rate between two values.Basic CalculatorA simple online calculator for everyday sums.Boat Loan CalculatorCalculate your monthly payment on a boat loan.Bond CalculatorEstimate a bond's price given face value, coupon and market yield.Budget CalculatorSplit your take-home income into needs, wants, and savings.Business Loan CalculatorCalculate monthly payment on a business loan including origination fee.Cash Back or Low Interest CalculatorCompare a manufacturer cash-back offer vs. a promotional low APR.CD CalculatorProject the maturity value of a Certificate of Deposit.College Cost CalculatorProject the future cost of college given inflation and years until enrollment.Commission CalculatorCalculate commission earned on a sale.Complex Number CalculatorCalculate with complex numbers online.Credit Card Payoff CalculatorSee how long a fixed monthly payment takes to clear a credit card balance.Currency CalculatorConvert between currencies using a manual exchange rate.Data Storage ConverterFree data storage converter for bytes, kilobytes, megabytes, gigabytes and terabytes.Debt Consolidation CalculatorCompare your current blended debt payments vs. one consolidation loan.Debt Snowball vs. Avalanche PlannerEnter every debt you owe and see the exact month-by-month order to pay them off two ways — Snowball (smallest balance first) and Avalanche (highest interest first) — with total interest for each strategy compared side by side.Debt-to-Income Ratio CalculatorLenders use DTI to judge how much of your income already goes to debt.Depreciation CalculatorCalculate straight-line depreciation for an asset.Down Payment CalculatorCalculate your down payment, loan amount, and whether you'll owe PMI.Emergency Fund CalculatorCalculate how much you need saved to cover 3–6 months of essential expenses.Energy ConverterFree energy converter for joules, calories, kilowatt-hours and BTU.Equation SolverSolve linear, quadratic and cubic equations and 2x2 systems.Estate Tax CalculatorEstimate federal estate tax owed above the exemption threshold.FHA Loan CalculatorEstimate payments including upfront and monthly mortgage insurance premium (MIP).Finance CalculatorCompound interest, loan and other finance sums in the calculator.Full Amortization Schedule GeneratorGenerate a complete month-by-month payment schedule for any loan — export it to CSV and see the balance payoff curve. This produces hundreds of exact calculated rows a chatbot cannot compute or hand you as a real file.Future Value CalculatorWhat will today's money be worth in the future?General Finance CalculatorTime-Value-of-Money: solve for Future Value given PV, PMT, rate and periods.HELOC CalculatorEstimate your available credit line and interest-only draw payment.Home Equity Loan CalculatorSee your available equity and estimated fixed loan payment.Hourly to Salary CalculatorConvert an hourly wage into annual, monthly and weekly salary equivalents.House Affordability CalculatorEstimate the maximum home price you can comfortably afford using the 28/36 rule.Inflation CalculatorSee what a past dollar amount is worth today (or in the future) after inflation.Interest Rate CalculatorSolve for the interest rate given a starting and ending value.Investment Interest CalculatorProject the growth of a lump-sum investment with compounding.Investment Portfolio RebalancerEnter your current holdings and target allocation — get the exact dollar amount to buy or sell in each asset class to rebalance, plus a live pie chart.IRR CalculatorCalculate the Internal Rate of Return for an initial investment and 3 years of cash flow.Job Offer Comparison ToolCompare two job offers beyond base salary — bonus, PTO value, benefits, and cost-of-living — to see which is actually worth more.Lease CalculatorEstimate a general equipment or asset lease payment.Length ConverterFree length converter for meters, feet, inches, kilometres and miles.Live Currency ConverterFetches live exchange rates from our currency API right now — not a guessed or outdated number a language model would make up.Marriage Tax CalculatorCompare combined tax filing jointly vs. as two single filers.Matrix CalculatorDeterminant, inverse and multiplication for matrices.Mortgage Extra-Payment "What-If" SimulatorDrag a live slider to see, in real time, exactly how many years and how much interest an extra monthly payment saves on your mortgage.Mortgage Payoff CalculatorSee how much time and interest an extra monthly payment can save.Mutual Fund CalculatorProject growth of a mutual fund investment including expense ratio drag.Net Worth TrackerTrack everything you own vs. everything you owe. Saves your entries in this browser so you can update it over time and watch the trend — something a stateless chatbot reply can never remember for you.Pay Stub GeneratorGenerate and print a real itemized pay stub with gross pay, tax withholding, deductions, and net pay — a formatted document, not just a spoken number.Payback Period CalculatorFind out how long it takes an investment to pay for itself.Payment CalculatorStandard loan payment calculator for any purpose.Pension CalculatorEstimate an annual defined-benefit pension payout.Personal Loan CalculatorCalculate your monthly payment on an unsecured personal loan.Present Value CalculatorWhat is a future sum of money worth today?Pressure ConverterFree pressure converter for pascal, bar, PSI, atmospheres and mmHg.Programmer CalculatorConvert and calculate in hex, binary, octal and decimal.Real Estate Appreciation CalculatorProject a property's future value and equity growth.Refinance CalculatorFind your breakeven point when refinancing to a new rate or term.Rent CalculatorEstimate a comfortable monthly rent budget using the classic 30% of gross income rule.Rental Property CalculatorEstimate cash flow, cap rate and cash-on-cash return for an investment property.Retirement CalculatorProject your retirement nest egg based on current savings and contributions.Retirement Withdrawal SimulatorSimulate spending down a retirement portfolio year by year with inflation-adjusted withdrawals and market growth — and see the exact year the money runs out, if ever.RMD CalculatorCalculate your Required Minimum Distribution using the IRS Uniform Lifetime Table.ROI CalculatorCalculate a simple return on investment percentage.Roth IRA CalculatorProject tax-free growth of a Roth IRA.Sales Tax CalculatorCalculate sales tax and total price, or back it out from a total.Savings CalculatorSee how a monthly savings habit grows over time.Self-Employment Tax CalculatorCalculate Social Security + Medicare tax owed on freelance/1099 net income.Simple Interest CalculatorInterest calculated only on the original principal — no compounding.Social Security CalculatorRough estimate of your monthly benefit based on average indexed earnings and claiming age.Speed ConverterFree speed converter for km/h, mph, knots and metres per second.Statistics Mode: Mean, Median, Std DevMean, median, standard deviation and more for a list of numbers.Student Loan / Repayment CalculatorCalculate your monthly student loan payment.Take-Home Paycheck CalculatorEstimate net pay per paycheck after federal tax and FICA.Temperature ConverterFree temperature converter for Celsius, Fahrenheit and Kelvin.Time ConverterFree time converter for seconds, minutes, hours, days, weeks and years.Traditional IRA CalculatorProject tax-deferred growth of a Traditional IRA.VA Mortgage CalculatorEstimate payments for a VA loan including the funding fee.Volume ConverterFree volume converter for litres, gallons, cups, millilitres and fluid ounces.Weight ConverterFree weight converter for kilograms, pounds, ounces, grams and stones.3D Geometry ViewerRotate seven 3D solids and calculate volume, surface area, faces, edges and vertices.3D Molecule ViewerRotate, zoom and switch between ball-and-stick and space-filling models of common molecules.4-Stroke Engine & Otto CycleWatch intake, compression, power and exhaust strokes with valves, spark and a pressure-volume diagram.AC Circuits: Resistor, Capacitor & InductorChange frequency and components and see voltage, current, phase and impedance in an AC circuit.Acid-Base LabAdd HCl or NaOH to water and watch a live pH meter and indicator colour.Acid-Base Titration SimulatorRun a full analytical titration bench: fill the burette, add titrant drop by drop or continuously, and watch the live pH meter and titration curve build as you go.Area Model Multiplication & the DistributiveSee multiplication as a rectangle, split it into four easier parts and watch the partial products add up.Atom BuilderBuild atoms from protons, neutrons and electrons and see the element, isotope and charge.Atomic Interactions: Lennard-Jones PotentialDrag two atoms and see the attractive and repulsive forces and the Lennard-Jones potential graph.Atomic Orbital VisualizerSee the shapes of s, p and d orbitals and rotate them in 3D.Balance Beam & TorqueDrag weights onto a seesaw and balance the torques on both sides.Balancing Act: Torque & SeesawBalance a plank with bricks, crates and people, learn torque, and work out a mystery mass.Balloons & Static ElectricityRub a balloon on a sweater and watch it stick to the wall, showing charge transfer and induced charge.Beam Bending & Stress SimulatorMove a load along a beam, see deflection, the bending moment diagram and whether it stays safe.Beer's Law Lab: Absorbance & ConcentrationShine light through a colored solution and see how absorbance depends on concentration, width and wavelength.Bending Light: Refraction, Reflection & PrismAim a laser at water, glass or diamond, see reflection and refraction with angles, or split white light in a prism.Bernoulli's Principle & Fluid FlowSqueeze a pipe and watch the fluid speed up while the pressure gauge drops.Blackbody Spectrum & Wien's LawChange temperature and watch the blackbody curve, peak wavelength and glow colour of a hot object.Blood Flow & Circulatory System SimulatorFollow blood from the heart through arteries, arterioles, capillaries and veins, and see how strongly flow depends on vessel radius.Bohr Model of HydrogenMake the electron jump between energy levels and see the photons absorbed and emitted.Buffer Solution SimulatorAdd acid and base to a buffer and to plain water side by side and watch which one resists pH change.Build a Nucleus: Protons, Neutrons & StabilityDrag protons and neutrons to build atoms from hydrogen to calcium and check isotopes and stability.Buoyancy & Density LabDrag objects into fluid and see when they float or sink, with the buoyant force.Calculus Grapher: Derivative & IntegralDraw a function and see its derivative, or draw the derivative and see the function.Calorimetry & Specific Heat LabDrop a hot metal into water, plot the temperatures and calculate the specific heat capacity.Capacitor Lab: BasicsChange plate area, separation and voltage to see capacitance, charge and stored energy.Car Transmission & Gear Ratio SimulatorShift through the gears of a gearbox and see the gear pair, engine rpm, wheel speed, torque and speedometer.Carbon Cycle Simulator: Reservoirs & FluxesSet emissions, deforestation and uptake rates and watch carbon flow between the atmosphere, ocean, land biosphere and fossil reserves in a real mass-balance model.Cardiac Cycle & Wiggers Diagram LabDrive the heart through atrial systole, ventricular systole and diastole, watch the valves open and close, and read a real Wiggers-style pressure graph.Catalyst & Activation EnergySee how a catalyst lowers the activation energy barrier and speeds a reaction.Cell Membrane & Osmosis SimulatorPlace a cell in a hypotonic, isotonic or hypertonic solution and watch water cross the membrane while a live graph tracks the cell's volume.Center of Mass & BalanceDrag weights on a beam and place the support so it balances at the centre of mass.Central Limit Theorem: Sampling DistributionDraw samples from any population and watch the sample means pile up into a bell curve.Charges and Fields: Electric Field & VoltagePlace positive and negative charges, drag them, and see electric field arrows and voltage colours with a live sensor.Chemical Equation BalancerPractise with 1,700+ real equations, or type your own and balance it with charges.Chemical Equilibrium SimulatorWatch the forward and reverse reactions balance and apply Le Chatelier's principle.Circuit Construction Kit: DC & AC Virtual LabBuild real circuits with batteries, bulbs, resistors, fuses, switches, wires, capacitors, inductors and household objects, then measure them with a voltmeter and an ammeter.Circuit LabWire two resistors in series or parallel and see voltage, current and power.Circular Motion & Centripetal ForceSwing a ball on a string and drag it to change the radius and speed.Climate Chemistry: CO₂ & TemperatureChange CO₂ levels and see the greenhouse effect warm the planet.Collision Lab: 2D Momentum & Kinetic EnergyCrash balls of different masses on a table and track total momentum and kinetic energy for bouncy or sticky collisions.Collision Theory SimulatorWatch molecules collide and see why only fast, well-oriented collisions react.Collisions & Momentum LabCrash two carts together and compare momentum and kinetic energy before and after.Color Theory LabBuild colour harmonies on a wheel and check text contrast against WCAG.Color Vision: How We See ColourMix red, green and blue flashlights or choose one wavelength and see how your three cone types respond.Conservation of Angular Momentum: SpinningPull a spinning skater's arms in and watch her spin speed up exactly as L = Iω is conserved, or drop one spinning disk onto another and see them lock together.Continental Drift & Plate Motion SimulatorDrag two plates and set their velocities to build convergent, divergent or transform boundaries, then watch mountains, rifts and earthquakes appear in a live cross-section.Coulomb's Law: Force Between ChargesDrag two charges along a ruler, change their size and sign, and see the electric force between them.Curve Fitting: Best-Fit Line & RegressionDrag data points and watch the best-fit line, quadratic and cubic curves and R² update.DC Motor Simulator: Torque, Speed & Back-EMFSpin a permanent-magnet DC motor against a load, watch it settle onto its torque-speed curve, and see it stall if the load is too heavy.Density Lab: Mass, Volume & Identify theWeigh mystery blocks, measure their volume by water displacement and work out the material from the density.Derivative VisualizerDrag a point along a curve and see the tangent line and the derivative graph appear.Diffraction Grating & Spectrometer LabShine light through a diffraction grating and watch the bright orders land exactly where d sinθ = mλ predicts, then try to overlap two colors' orders.Diffusion & Osmosis SimulatorSee solute and water move across a membrane and find out why water follows the higher concentration.Digital Filter Designer: Low-Pass & High-PassDesign a real RC low-pass or high-pass filter, watch its Bode magnitude plot draw live, and see exactly how much a signal is attenuated at any frequency.Digital Logic Gate SimulatorBuild circuits from AND, OR, NOT, NAND, NOR, XOR and XNOR gates, wire toggleable inputs to outputs and watch every signal propagate live, with an auto-generated truth table, Boolean expression, Karnaugh map and a NAND/NOR-only challenge mode for whatever you build.Distillation Setup LabAssemble a full distillation apparatus, fix thermometer and cooling-water mistakes, heat carefully, and read the boiling-point plateau as you separate two liquids.DNA Replication & Protein Synthesis SimulatorStep through DNA replication, transcription and translation of a short gene using real base-pairing and a genetic code table, then introduce a mutation and classify its effect.DNA Replication GameDrag the matching bases onto the unzipped DNA strand to build the copy, or type your own sequence.Doppler Effect SimulatorMove a sound source and an observer and hear how the pitch changes with speed.Double Slit & DiffractionChange wavelength and slit spacing and see the interference pattern and its intensity graph.Earthquake & Seismic Wave LaboratoryTrigger a virtual earthquake, watch P, S and surface waves radiate outward, read live seismograph traces at three stations, and triangulate the epicenter from S−P intervals.Electric Field & Charges SimulatorDrag positive and negative charges around and watch the field lines and forces react.Electric Potential & Equipotential Lines LabDrag a test point around two charges and read its potential and field live, then find where moving along an equipotential line takes zero work.Electrical Power Transformer & TransmissionStep a generator's voltage up through an ideal transformer, send the power down a resistive transmission line, and watch the current, I²R line loss and transmission efficiency all update live against the same delivered power.Electrolysis of WaterSplit water into hydrogen and oxygen and watch the bubbles collect in a 2:1 ratio.Electroplating Cell & Faraday's LawPlate an object with copper, silver, nickel, zinc or gold and calculate the mass and thickness from the current.Emission Spectrum ViewerA virtual spectrometer: 20 gases, emission, absorption and hot-solid views, an adjustable slit, UV to infrared, a hydrogen energy-level diagram and a mystery-element challenge.Energy Forms and Changes: Heat TransferHeat or cool an iron block, a brick and water, put them together and watch thermal energy flow with a live energy chart.Energy Skate ParkDrag a skater around a track and watch kinetic, potential and thermal energy trade places.Enthalpy & Activation Energy DiagramDrag the reactant, peak and product levels of an energy profile and see ΔH, Ea and the effect of a catalyst.Enzyme Activity SimulatorChange substrate, temperature, pH and inhibitors and watch the reaction rate of an enzyme.Enzyme Kinetics LaboratoryChange substrate, enzyme, temperature, pH and inhibitors, and watch a live Michaelis-Menten curve - then switch to a Lineweaver-Burk plot to estimate Vmax and Km yourself.Exoplanet Detection Lab: Transit & RadialTune a planet's size, mass and orbit and see whether the transit dip or the radial-velocity wobble is strong enough to detect above real instrument noise.Exponential Growth & Decay ExplorerCompare multiplying and adding growth for bacteria, savings, radioactive decay and viral videos, with a log scale option.Faraday's Law & Generator LabMove a magnet through a coil to light a bulb, or spin the generator and watch the induced voltage.Flower Anatomy & Pollination SimulatorClick a flower's parts to learn stigma, style, ovary, anther, filament, petal and sepal, then choose a pollination method and watch a fruit develop.Fluid Pipe Network & Pump Sizing LabSize a pipe run and a centrifugal pump, watch water flow through the pipe live, and see exactly where the pump curve and system curve meet to set the real operating flow and head.Forces & Friction SimulatorPush a block and explore Newton's laws, static and kinetic friction.Forces and Motion: Newton's Second LawPush a cart with different forces and friction and see acceleration, speed and net force.Fossil Formation & Geological Time SimulatorBury an organism and control burial depth, oxygen exposure and time to see it fossilize through compaction and mineral replacement, then read the sediment layers using relative dating.Fourier: Making WavesDrag harmonic amplitudes and watch sine waves add up to square, sawtooth and triangle waves.Fraction Builder: Compare, Add & EquivalentBuild two fractions with bars, circles and a number line, compare them, find equivalent fractions and add them.Free Fall & Motion GraphsDrop or throw an object and watch position and velocity graphs build in real time.Galvanic CellBuild a battery from two metals and watch electrons flow, with the cell voltage.Gas Laws SimulatorChange temperature, volume and particles to see pressure follow PV = nRT.Gear Train & Mechanical Advantage DesignerBuild a real two-stage compound gear train, watch the gears mesh and turn, and read off the true speed and torque the math predicts.Gear Train SimulatorDrag gears together to mesh them, then see speed and torque change through the train.Geometric TransformationsDrag a shape to translate, rotate and scale it and see the transformation matrix.Geothermal Energy & Earth's Interior SimulatorDrill a virtual geothermal well into an Earth cross-section and compute real temperature-versus-depth, extracted thermal energy and electrical power output.Gravitational Field & Escape Velocity LabPick a world, launch a rocket straight up and see whether it falls back or truly escapes, with the real field strength and escape speed live.Gravity & Orbits SandboxDrag planets, set their velocity and watch gravity build orbits, slingshots and collisions.Gravity Force LabDrag two masses and change their size to see how the gravity force depends on mass and distance.Greenhouse Effect & Earth's Energy BalanceChange the sun, reflectivity and greenhouse gases and see the surface temperature of Earth, Venus, Mars or Snowball Earth.Groundwater & Aquifer SimulatorWatch the water table rise and fall with rainfall and pumping, place a well, and see a contamination plume spread toward it through a permeable aquifer.Gyroscopic Precession LabSpin a wheel fast, hang a weight off its axle, and watch the whole axle slowly sweep around instead of falling - real torque-induced precession.Heart Pump & Cardiac CycleFollow one heartbeat through the four chambers, valves, ECG trace and blood pressure.Heat Conduction Through a Wall: Fourier's LawChange a wall's thickness, area and material, or stack layers of brick and insulation in series, and watch the heat flow and temperature gradient update live using Fourier's law.Heat Exchanger Design LabSwitch between counter-flow and parallel-flow, size a real heat exchanger, and watch the hot and cold temperature profiles run the length of the unit while effectiveness-NTU and LMTD agree on the same heat duty.Heat Exchanger Simulator: Parallel-Flow vsRun a hot and a cold fluid stream through a simple exchanger in parallel-flow or counter-flow, set the inlet temperatures, flow rates and heat transfer area, and compare the outlet temperatures, LMTD and effectiveness live.Heating Curve ExperimentAdd heat to ice and watch temperature versus time, including the flat melting and boiling plateaus.Hooke's Law: Springs and ForcesPull a spring with your mouse and see the force grow in proportion, with a force-displacement graph.Hubble's Law & Redshift LabWatch a galaxy's spectral lines redshift with distance, plot a Hubble diagram, and measure the expansion rate of the universe for yourself.Human Digestion SimulatorBuild a meal, feed it through the digestive tract, and watch real enzymes break carbohydrates, protein and fat down while a graph tracks nutrient absorption over time.Human Musculoskeletal Movement SimulatorPick a joint, activate a muscle, and watch it flex the joint against a load - with live torque, mechanical advantage and a real load-versus-force experiment.HVAC & Heat Pump SimulatorSet a thermostat and watch a heat pump cycle move heat in or out of a house.Hydraulic Press & Pascal's PrinciplePush a small piston and lift a car with a big one, and see how force, area and distance trade off.Inclined Plane SimulatorDrag the block and tilt the ramp yourself, flick it, and watch forces, speed and energy update live.Integral & Area Under CurveDrag the limits, choose the number of rectangles and compare Riemann sums with the exact area.Ionic vs Covalent BondsChange electronegativity difference and watch bonds go from covalent to polar to ionic.Isotopes & Average Atomic Mass MixerMix isotopes of chlorine, copper, boron and more and see the weighted average atomic mass on the periodic table.John Travoltage: Static Electricity & SparksRub John's foot on the carpet, collect charge, and bring his finger close to the doorknob to make a spark.Kepler's Laws of Planetary MotionChange orbit size and shape, see equal-area sectors and check the period–distance law.Kinematics Graph MatcherDrag a runner so its position-time graph matches the target line, then get a score.Kirchhoff's Rules: Multi-Loop Circuit LabChange the EMFs and resistors in a real two-loop circuit and watch all three branch currents solve live from Kirchhoff's voltage and current laws.Ladybug Motion 2D: Velocity & AccelerationDrag a ladybug around, or let it move in a line, circle or ellipse, and see its velocity and acceleration arrows change live.Le Chatelier's PrincipleChange concentration, temperature and pressure on N₂ + 3H₂ ⇌ 2NH₃ and watch the equilibrium shift.LED Circuit Designer & Resistor CalculatorBuild LED circuits with a battery, resistor, LED, switch and meters, watch real current and brightness, break them on purpose, and use 11 resistor calculators.Lens & Mirror Ray DiagramDrag the object and the focal point and watch the principal rays form the image.Light Refraction SimulatorBend a light ray between air, water, glass and diamond and find the critical angle.Limiting Reagent & Stoichiometry CalculatorType any reaction, enter grams of each reactant and find the limiting reagent and yield.Linear Equation ExplorerChange slope and intercept or drag two points to see the line, its equation and intercepts.Logistic Growth & Carrying Capacity LabRun the real logistic growth equation, add a harvesting rate, and find the maximum sustainable yield or push a population to collapse.Lunar Lander: Land Softly Physics GameFire the engine and tilt the lander to touch down softly on the pad, on the Moon, Mars or Earth.Magnet & Compass: Magnetic Field LinesDrag a bar magnet and a compass to see the magnetic field direction, strength and field lines.Magnetic Field & Compass SimulatorDrag a bar magnet around a grid of compasses and watch the field lines turn.Magnets and ElectromagnetsPower a coil with a battery, add loops, flip the current and drag a compass to see the field.Masses and Springs: Bounce LabHang masses on two springs, compare stiffness, gravity and damping, and measure the bounce period.Material Fatigue & S-N Curve LabCycle a loaded part through repeated stress, watch the waveform run, and read off the S-N curve exactly how many cycles it should survive before it fails.Mineral Identification LaboratoryRun real mineral tests — streak, Mohs hardness, luster, cleavage, density by displacement, magnetism and acid reaction — to identify an unknown specimen.Molarity & Dilution SimulatorDissolve a solute, see the concentration, and work out how much water to add to dilute it.Molecule BuilderAdd atoms and see which real molecule you have built, with a 3D model and name.Molecule Polarity SimulatorChange atom electronegativity and see bond dipoles, the net dipole and molecule polarity.Molecule ShapesDrag bonds and lone pairs onto a central atom, rotate it in 3D, and explore real molecules.Molecules and Light: Greenhouse EffectShine microwave, infrared, visible or ultraviolet light on molecules and see which absorb it and what happens.Moon Phases SimulatorMove the Moon around its orbit and see what phase looks like from Earth.Mountain Building SimulatorCompress a crustal block with adjustable plate velocity, rock strength and erosion, and watch a mountain range grow in real time cross-section, surface and stress views.Moving Man: Position, Velocity & AccelerationDrag the person along the track and watch position, velocity and acceleration graphs build.Natural Selection SimulatorWatch fur colour evolve in a bunny population as predators hunt and the environment changes.Neuron & Action Potential SimulatorStimulate a neuron and watch it fire (or fail to fire) an action potential, with a live resting → threshold → depolarization → repolarization → hyperpolarization voltage graph.Neuron Firing SimulatorStimulate a neuron and watch the action potential travel along the axon.Normal Modes: Coupled OscillatorsDrag masses on springs, excite each normal mode and see how every motion is a mix of modes.Ocean Acidification LabRaise atmospheric CO₂ and watch ocean pH fall and carbonate ions disappear, using the real carbonic acid chemistry behind ocean acidification.Ocean Acidification SimulatorSee how dissolved CO₂ lowers ocean pH and threatens shell-forming animals.Ohm's Law SimulatorChange voltage and resistance and see the current, the V = I R equation letters and a bulb brightness change.Orbital HybridizationStep through promotion, hybridisation and bonding for nine molecules with a rotating 3D hybrid-orbital picture.Orbital Motion & Gravity SimulatorLaunch a planet around a star and see circular, elliptical and escape orbits.Organic Reaction Pathways GameDrag reagents onto compounds to convert ethane, ethene, ethanol, ethanoic acid and esters, and take route challenges.Ozone Layer & UV Radiation LabRun a simplified Chapman cycle: balance ozone production against natural and CFC-driven catalytic destruction, and watch surface UV respond.Paper Chromatography & Rf ValuesSeparate the dyes of an ink on paper, choose the solvent and measure the Rf value of each dye.Pendulum Lab SimulatorExplore period, gravity and energy with a swinging pendulum.Periodic Trends ExplorerColour the periodic table by radius, electronegativity or ionisation energy and see the trends.pH Scale SimulatorTest everyday liquids and see pH, hydrogen and hydroxide ions, and acid or base.Photoelectric Effect SimulatorShine light on a metal and see when electrons are emitted, and how fast.Photosynthesis & Limiting FactorsMove the lamp, change CO₂ and temperature and count the oxygen bubbles from a pond plant.Photosynthesis Simulator: Inside theZoom inside a chloroplast and control light, CO₂, temperature and water to see the light-dependent and light-independent reactions speed up, slow down or stall.Phototropism & Gravitropism LabRotate the pot and move the light, predict which way the shoot and root will grow, then run the simulation and check your prediction.PID Control System SimulatorTune a PID controller driving a simulated DC motor toward a target speed, watch the response live, and feel what each of P, I and D actually does.PID Controller Tuning LabTune proportional, integral and derivative gains on a real first-order plant, watch the closed-loop step response redraw with a sweeping time marker, and read off the true overshoot, settling time and steady-state error.Pipe Flow & Reynolds Number SimulatorPick a fluid and a pipe, set the flow rate, and watch whether it flows in smooth layers or chaotic turbulence.Plant Genetics & Mendelian InheritanceCross two parent plants for flower colour, seed shape or height, build the Punnett square, then breed real offspring and compare the ratio to Mendel's theory.Plant Hormone SimulatorDial up auxin, gibberellin, cytokinin, ethylene and ABA and watch a plant bend toward light, stretch taller, branch out, ripen fruit or drop its leaves.Plant Nutrient Deficiency LaboratoryDiagnose a mystery plant's hidden nutrient deficiency from real symptom patterns - which leaves are affected and how - then submit your answer.Plant Transpiration LaboratoryControl humidity, temperature, wind and stomatal aperture in a sealed chamber, zoom on the stomata, and measure the transpiration rate live.Plant Water Transport: Xylem SimulatorFollow water from root to leaf through the xylem, and see how transpiration, root pressure and vessel width set the water's speed and pressure.Plate Tectonics & EarthquakesWatch plates collide, spread apart and slide past each other to build volcanoes, ridges and earthquakes.Plinko Probability: Galton BoardDrop balls through pegs and watch the bell-shaped binomial distribution build, with the theory curve.Polarization of Light: Malus's Law LabTurn a polarizing filter and watch the transmitted light dim exactly as I = I0 cos²θ predicts, then bring light back through crossed filters with a third one.Precipitation Reactions LabMix real quantities of ionic solutions, watch a staged nucleation-and-settling animation, check Q against Ksp, then filter, weigh and calculate percent yield.Predator-Prey Population SimulatorWatch rabbit and fox populations rise and fall with the Lotka-Volterra model.Probability LabFlip coins and roll dice thousands of times and compare results with theory.Projectile Data Lab: Air Resistance & TargetFire golf balls, pumpkins and pianos with and without air resistance and collect a table of ranges.Projectile Motion SimulatorLaunch a projectile and watch its path, range and max height change live.Pulley System SimulatorPull the rope, see how more rope strands cut the force you need but lengthen the pull.Punnett Square CalculatorCross two parents and get genotype and phenotype ratios, for one trait or two.Quadratic Function ExplorerDrag a, b and c to see the parabola, roots, vertex and discriminant change.Quantum Coin TossToss a quantum coin, put it in superposition, measure it and see interference bring it back to heads.Quantum Measurement: Stern-Gerlach ExperimentSend spin particles through analyzers along Z and X and see how measurement changes the state.Quantum Wave InterferenceFire photons, electrons or neutrons one at a time and watch the wave pattern build dot by dot.Radioactive Decay & Half-Life SimulatorWatch hundreds of unstable atoms decay at random and compare the count with the half-life curve.RC Circuit & Capacitor SimulatorCharge and discharge a capacitor through a resistor and watch voltage and current change.Reaction Mechanism & Rate-Determining StepSee a two-step mechanism as an energy profile, drag the peaks and find the slowest step and rate law.Reaction Rate SimulatorChange temperature and concentration and see how fast a reaction goes.Redox TrackerAnalyse any redox reaction you type, see who is oxidised and reduced, then test yourself.Reflex Arc & Nervous System SimulatorTrigger a stimulus and watch it race through the reflex arc, then compare a fast one-synapse knee-jerk reflex with a slower multi-synapse withdrawal reflex.Reinforced Concrete Beam DesignerPick a beam's width, depth, concrete and steel strengths and rebar, and watch the moment capacity and the ductile/brittle reinforcement check update live.Resistance in a WireChange a wire's length, thickness and material and watch electrons collide and the resistance change.Resonance Lab: Driven OscillatorsShake five springs and masses at different frequencies and see the one whose natural frequency matches swing wildly.Resonance Structures & DelocalisationSee the resonance forms of ozone, nitrate, carbonate, nitrite and benzene and the averaged hybrid.Respiratory System & Lung VentilationChange breathing rate, tidal volume, airway resistance and lung compliance, and watch the lungs and alveoli move air and exchange gas in real time.Rock Cycle LaboratoryDrag a rock sample through weathering, compaction, heat and pressure and watch it transform between igneous, sedimentary and metamorphic rock.Rocket Thrust & Launch SimulatorSet fuel, engine efficiency and throttle, launch a rocket and see altitude and speed graphs.Rutherford Scattering: Discovering the NucleusFire alpha particles at gold atoms and compare the plum pudding and nuclear models.Sediment Transport & River Erosion LabAdjust slope, discharge, channel width and grain size and use the real Hjulström curve to predict whether a river erodes, transports or deposits sediment — then add a dam and watch downstream 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CounterCounts your shooting motions and checks your follow-throughBeginner Workout PlansSix step-by-step plans: full body, push-ups, squats, core, 5K and mobilityBiceps Curl CounterCounts every biceps curl with your camera and tells you to curl higherBoxing & MMA Round TimerRounds with bell, 10-second warning clap and voice, presets for boxing and MMABoxing Punch CounterCounts every jab, cross and hook with your cameraCalories Burned CalculatorCalories burned by 37 activities, using MET values and your weightCamera Burpee CounterCounts burpees when you drop to the floor and stand back upCamera High Knees & Mountain Climber CounterCounts high knees or mountain climbers with the cameraCamera Jump Rope CounterCounts your jumps with the camera, with or without a ropeCamera Jumping Jack CounterCounts jumping jacks with your camera and says each numberCamera Lunge CounterCounts lunges with the camera and checks your front kneeCamera Pull-Up CounterCounts pull-ups when your chin clears the bar, any camera angleCamera Push-Up CounterYour camera counts every push-up and checks your form, from any angleCamera Sit-Up & Crunch CounterCounts sit-ups or crunches with your camera, from any angleCamera Squat CounterCounts your squats with the camera and checks depth, any angleCamera Workout ModeChain squats, push-ups, planks and more: the camera counts and the voice coachesChest & Shoulder Workout at HomePush-up variations and dumbbell presses with a 3D coachCricket Batting & Bowling AnalyzerBatting and bowling actions: arm speed, elbow, front knee, head stabilityCustom Workout Builder with Voice CoachChoose from 120+ exercises, set reps & sets, then follow the voiceCycling Calculators: Speed, Power, Gears & FTPSpeed/time/distance, watts needed, gear ratio and FTP zones in one pageDeload & Recovery Readiness AdvisorDaily readiness score: train hard, go light, rest or deloadDesk Exercise Reminder for Office WorkersMovement break reminders with 1-5 minute voice-guided desk routinesDesk Posture CheckerWebcam watches your posture and reminds you to sit up and stretchDiet & Meal Planner with Shopping ListCalorie-matched meal plans with macros and a shopping listDOTS & Wilks CalculatorPowerlifting score from squat, bench, deadlift and body weightDumbbell Full Body WorkoutFull body, upper body and lower body dumbbell workoutsDynamic Warm-Up Routine5-minute warm-ups for any workout, legs or upper bodyExercise Library with Animations170 exercises with animated demos, muscles and how-to cuesExercise Timer with VoiceType your exercises, set work and rest, and a voice calls each one outFFMI CalculatorLean mass, fat mass and FFMI with a muscularity ratingFitness Blog & Guides9 practical fitness guides: push-ups, reps, protein, stretching and moreFitness Test ScorecardRate your fitness by age and sex: push-ups, sit-ups, plank and 1.5-mile runFitness Tools HubFind the right fitness tool by goal: lose fat, get stronger, stretch, trackFood Calorie & Macro Lookup + Daily Diary150+ foods with calories, protein, carbs, fat and a daily food diaryGentle Rehab Routines: Back, Knee, Shoulder &Voice-guided gentle routines with 3D demos and clear safety notesGlute Bridge CounterCounts every glute bridge and prompts you to lift higherGlute Workout at HomeBridges, kicks and thrusts with a 3D demo and voice coachGolf Swing AnalyzerRecord or load a swing: tempo, rotation, head movement, compare two swingsGPS Run Tracker with MapTrack runs, walks and rides: distance, pace, splits, route map, GPX exportHeart Rate Zones CalculatorFind your 5 training zones and max heart rate by ageHip Hinge & Deadlift CounterCounts deadlifts, good mornings and hip hingesIdeal Weight CalculatorDevine, Robinson, Miller & Hamwi formulas plus a healthy BMI rangeInteractive Muscle MapTap a muscle to see what it does and the best exercises for itKick CounterCounts front, side and roundhouse kicks with your cameraKids PE Challenges & Class ScoreboardAnimal workouts, brain breaks and 60-second challenges with a scoreboardLateral & Front Raise CounterCounts every lateral or front raise to shoulder heightLeft-Right Balance & Symmetry TestCompare your left and right side: balance, squat, shoulders, push-upsLeg Day at HomeQuads, hamstrings, glutes and calves with a 3D coachLeg Raise CounterCounts lying leg raises and checks you lift toward verticalMacro CalculatorDaily calories and protein, carb and fat grams for your goalMeditation Timer with Guided Breathing & Bells3-30 minute sessions: guided breathing, body scan or silent with bells and ambient soundsMobility Screening TestDeep squat, toe touch, overhead reach and lunge, scored 0-3Morning Energy Workout5 or 10 minute wake-up workouts, including a no-jumping optionOne-Rep Max CalculatorEstimate your max lift from any set, with a training-weights tablePace Band & Split CalculatorPrintable splits for any race: even, negative or fast-start strategyPedometer for Your PhoneCounts steps with your phone's motion sensors, with distance and caloriesPersonal Records BoardAll your best lifts, rep records and run times in one placePlank Timer with Form CheckTimes your plank and warns you when your hips sag or liftProgress Photos with Before/After SliderPrivate photo timeline with a drag-to-compare before and after sliderPronunciation PracticeHear a model voice, say it yourself and get a word-by-word scoreProtein Intake CalculatorHow many grams of protein you need per day and per mealPush-Up Coach with VoicePick reps, sets & speed, then a voice says Down, Up, 1, 2, 3Quiet Cardio WorkoutApartment-friendly, low-impact cardio with a 3D coachRace Time Predictor & Training PacesPredict 5K to marathon times and get easy, tempo and interval pacesRep & Set TrackerLog weight, reps and sets, with an automatic rest timerRest Timer with VoiceRest timer between sets with voice alerts and auto-restartRun/Walk Interval Timer & Couch to 5KVoice-guided run/walk intervals: Couch to 5K, custom and speed playRunning Cadence & Music BPM CalculatorSteps per minute for your pace, and the pace for a song's BPMSenior Chair Exercises & Balance TestsChair workouts for older adults plus 30-second chair stand and balance testsShoulder Press CounterCounts every overhead press and checks you lock outSteps to Distance CalculatorConvert steps to km/miles, time and calories (and back)Strength Program CalculatorWeights for popular strength programs from your 1RMStrength Standards CalculatorHow strong are you? Bench, squat, deadlift levels by body weightStrength Workout for RunnersSingle-leg strength, glutes and core to run strongerStretch Routine Guide8 guided stretching routines with timers, sides and breathing cuesStretching Guides with Animations18 stretches with animated demos, steps, benefits and hold timesSweat Rate CalculatorHow much you sweat per hour and how much to drinkSwimming Calculators: Pace, Laps, Calories &Pace per 100 m, lap converter, calories burned and critical swim speedTennis Stroke AnalyzerForehand, backhand and serve: speed, rotation, knee bend, compare strokesText Reader with Highlighted WordsRead any text aloud and follow the highlighted wordTriceps Dip CounterCounts chair or bar dips from any angleVO2 Max CalculatorCooper, 1.5-mile, Rockport walk and resting heart rate methodsVoice CounterA voice counts out loud for you: up, down, by 2s, 5s or 10sWaist-to-Height & Waist-to-Hip RatioHealth-risk ratios from your waist, hip and heightWall Sit TimerTimes your wall sit and warns when you slide up or too lowWarm-Up Sets CalculatorRamp-up sets to your working weight, rounded to platesWeekly Workout PlannerChoose your days, goal and equipment, get a full week of workoutsWeight & Body Measurements TrackerTrack weight, waist, chest, hips, arms with charts and a goal lineWeight Loss Timeline CalculatorHow long to reach your goal weight, with a date and weekly projectionWorkout GeneratorPick muscles, equipment and minutes, get a full workout with animationsWorkout Log & History TrackerStreaks, a 20-week heat map and a log of every workoutYoga Flow BuilderBuild your own yoga flow from 50+ poses and let a voice guide youYoga Pose CheckerCamera checks your yoga pose joint by joint and tells you what to fixBrain Type Quiz — Fast Thinker, OverthinkerA short quiz that reveals your brain type with a shareable personality cardBroke Score — How Broke Are You Really?A funny but real 0-100% broke score from your income, spending and savingsCategory Rush GameName something in the category with a random letterClean Jokes TellerThousands of clean jokes with a punchline revealCompare Yourself to the WorldSee your estimated income and sleep percentile vs the world, based on cited averagesDigital Life Report — Brain Performance ScoreIn-page typing and reaction tests plus your habits, combined into one Brain Performance ScoreFive in a RowGomoku vs computer or a friend on one screenFocus Score Test — Real Timed Attention TestA real in-browser go/no-go attention test with a measured, timed scoreFuture Net Worth Simulator — Spend vs InvestCompare two real compound-interest projections: keep spending vs start investingGirls' Night Party GamesMost likely to... and Spill the Beans promptsGroup Story BuilderBuild a silly story one sentence at a timeHousie Tambola Number CallerNumber caller and ticket generator for HousieHow Well Do You Know Me?Friend and bride/groom quiz questionsLife in Numbers — How Much of Your LifeSee how many years you've spent asleep and on your phone, from your own numbersMafia Role DealerDeal secret Mafia roles and read the narrator scriptMancalaClassic Mancala vs computer or two playersMove-Out Readiness ScoreA real 50/30/20-style affordability score for moving out on your ownNever Have I Ever Questions1,200+ clean Never Have I Ever promptsOne Sentence About Your LifeA few quick picks generate one blunt, reflective sentence about where you're atOverthinking Score — Rumination Self-CheckA short self-report quiz based on real rumination-scale concepts, with a percentile scoreParty Bingo CardsBridal, baby shower, mehndi, birthday and girls' night bingoPass the Bomb GameHidden-timer party game: name one and pass it onPictionary Word GeneratorEasy, medium and hard drawing words with a timerRapid Fire Questions10 quick questions, 5 seconds eachRarity Score — How Rare Are You?An 8-question quiz that reveals how rare your everyday habits really areRiddles with AnswersBrain-teasing riddles, answer hidden until you tapRideshare Driver Profit Reality CheckReal effective hourly take-home after true vehicle costs, vs local minimum wageSilly Would You RatherAbsurd dilemmas with a group vote counterSleep Debt Calculator — Real Nights OwedReal arithmetic on how many full nights of sleep you're behind onSmarter Than Average QuizA 6-question logic trick-quiz with a percentile score vs a stated averageSticks GameTake 1 to 3 sticks; last stick losesSubscription Cost Reality CheckAdd your subscriptions and see the real annual total plus relatable comparisonsTeam Trivia BattleTeam quiz night with 4,600+ questionsText Personality AnalyzerPaste your own text for a heuristic style read — confident but impatient? Curious and detailed?Time Wasted on Phone — Lifetime CalculatorReal arithmetic on how many years of your life you'll spend on your phoneTongue Twister Challenge200+ tongue twisters to say three times fastTruth or Dare GeneratorClean truth and dare prompts, no repeatsTwo Truths and a LieTopic prompts and a score of who fooled the groupUndercover Word GameSpy word party game, pass one phone aroundWheel of NamesAdd names, spin the wheel and pick a fair random winner.Where Should You Live? Personality ArchetypeA fun quiz matching your preferences to a place archetype — not real relocation adviceWho Am I? Guessing GameHeads-up charades with a timer, 400 wordsWould You Rather Questions4,500 would-you-rather dilemmas3-Way Loan Comparison ToolCompare up to three real loan offers side by side — payment, total interest, and total cost — so you can see instantly which offer actually wins.401 CalculatorProject your 401(k) balance including employer match.529 College Savings Plan CalculatorProject tax-advantaged 529 plan growth toward a future college cost goal.Amortization CalculatorSee exactly how each payment splits between principal and interest over the life of your loan.Annuity CalculatorProject the future value of a stream of regular payments.Annuity Payout CalculatorConvert a lump sum into a guaranteed monthly payout.APR CalculatorSee the true annual cost of a loan once lender fees are blended in.Area ConverterFree area converter for square metres, square feet, acres and hectares.Auto Lease CalculatorEstimate your monthly lease payment using the money factor method.Auto Loan CalculatorCalculate your monthly car payment including trade-in and sales tax.Average Return CalculatorCalculate the compound annual growth rate between two values.Basic CalculatorA simple online calculator for everyday sums.Boat Loan CalculatorCalculate your monthly payment on a boat loan.Bond CalculatorEstimate a bond's price given face value, coupon and market yield.Budget CalculatorSplit your take-home income into needs, wants, and savings.Business Loan CalculatorCalculate monthly payment on a business loan including origination fee.Cash Back or Low Interest CalculatorCompare a manufacturer cash-back offer vs. a promotional low APR.CD CalculatorProject the maturity value of a Certificate of Deposit.College Cost CalculatorProject the future cost of college given inflation and years until enrollment.Commission CalculatorCalculate commission earned on a sale.Complex Number CalculatorCalculate with complex numbers online.Credit Card Payoff CalculatorSee how long a fixed monthly payment takes to clear a credit card balance.Currency CalculatorConvert between currencies using a manual exchange rate.Data Storage ConverterFree data storage converter for bytes, kilobytes, megabytes, gigabytes and terabytes.Debt Consolidation CalculatorCompare your current blended debt payments vs. one consolidation loan.Debt Snowball vs. Avalanche PlannerEnter every debt you owe and see the exact month-by-month order to pay them off two ways — Snowball (smallest balance first) and Avalanche (highest interest first) — with total interest for each strategy compared side by side.Debt-to-Income Ratio CalculatorLenders use DTI to judge how much of your income already goes to debt.Depreciation CalculatorCalculate straight-line depreciation for an asset.Down Payment CalculatorCalculate your down payment, loan amount, and whether you'll owe PMI.Emergency Fund CalculatorCalculate how much you need saved to cover 3–6 months of essential expenses.Energy ConverterFree energy converter for joules, calories, kilowatt-hours and BTU.Equation SolverSolve linear, quadratic and cubic equations and 2x2 systems.Estate Tax CalculatorEstimate federal estate tax owed above the exemption threshold.FHA Loan CalculatorEstimate payments including upfront and monthly mortgage insurance premium (MIP).Finance CalculatorCompound interest, loan and other finance sums in the calculator.Full Amortization Schedule GeneratorGenerate a complete month-by-month payment schedule for any loan — export it to CSV and see the balance payoff curve. This produces hundreds of exact calculated rows a chatbot cannot compute or hand you as a real file.Future Value CalculatorWhat will today's money be worth in the future?General Finance CalculatorTime-Value-of-Money: solve for Future Value given PV, PMT, rate and periods.HELOC CalculatorEstimate your available credit line and interest-only draw payment.Home Equity Loan CalculatorSee your available equity and estimated fixed loan payment.Hourly to Salary CalculatorConvert an hourly wage into annual, monthly and weekly salary equivalents.House Affordability CalculatorEstimate the maximum home price you can comfortably afford using the 28/36 rule.Inflation CalculatorSee what a past dollar amount is worth today (or in the future) after inflation.Interest Rate CalculatorSolve for the interest rate given a starting and ending value.Investment Interest CalculatorProject the growth of a lump-sum investment with compounding.Investment Portfolio RebalancerEnter your current holdings and target allocation — get the exact dollar amount to buy or sell in each asset class to rebalance, plus a live pie chart.IRR CalculatorCalculate the Internal Rate of Return for an initial investment and 3 years of cash flow.Job Offer Comparison ToolCompare two job offers beyond base salary — bonus, PTO value, benefits, and cost-of-living — to see which is actually worth more.Lease CalculatorEstimate a general equipment or asset lease payment.Length ConverterFree length converter for meters, feet, inches, kilometres and miles.Live Currency ConverterFetches live exchange rates from our currency API right now — not a guessed or outdated number a language model would make up.Marriage Tax CalculatorCompare combined tax filing jointly vs. as two single filers.Matrix CalculatorDeterminant, inverse and multiplication for matrices.Mortgage Extra-Payment "What-If" SimulatorDrag a live slider to see, in real time, exactly how many years and how much interest an extra monthly payment saves on your mortgage.Mortgage Payoff CalculatorSee how much time and interest an extra monthly payment can save.Mutual Fund CalculatorProject growth of a mutual fund investment including expense ratio drag.Net Worth TrackerTrack everything you own vs. everything you owe. Saves your entries in this browser so you can update it over time and watch the trend — something a stateless chatbot reply can never remember for you.Pay Stub GeneratorGenerate and print a real itemized pay stub with gross pay, tax withholding, deductions, and net pay — a formatted document, not just a spoken number.Payback Period CalculatorFind out how long it takes an investment to pay for itself.Payment CalculatorStandard loan payment calculator for any purpose.Pension CalculatorEstimate an annual defined-benefit pension payout.Personal Loan CalculatorCalculate your monthly payment on an unsecured personal loan.Present Value CalculatorWhat is a future sum of money worth today?Pressure ConverterFree pressure converter for pascal, bar, PSI, atmospheres and mmHg.Programmer CalculatorConvert and calculate in hex, binary, octal and decimal.Real Estate Appreciation CalculatorProject a property's future value and equity growth.Refinance CalculatorFind your breakeven point when refinancing to a new rate or term.Rent CalculatorEstimate a comfortable monthly rent budget using the classic 30% of gross income rule.Rental Property CalculatorEstimate cash flow, cap rate and cash-on-cash return for an investment property.Retirement CalculatorProject your retirement nest egg based on current savings and contributions.Retirement Withdrawal SimulatorSimulate spending down a retirement portfolio year by year with inflation-adjusted withdrawals and market growth — and see the exact year the money runs out, if ever.RMD CalculatorCalculate your Required Minimum Distribution using the IRS Uniform Lifetime Table.ROI CalculatorCalculate a simple return on investment percentage.Roth IRA CalculatorProject tax-free growth of a Roth IRA.Sales Tax CalculatorCalculate sales tax and total price, or back it out from a total.Savings CalculatorSee how a monthly savings habit grows over time.Self-Employment Tax CalculatorCalculate Social Security + Medicare tax owed on freelance/1099 net income.Simple Interest CalculatorInterest calculated only on the original principal — no compounding.Social Security CalculatorRough estimate of your monthly benefit based on average indexed earnings and claiming age.Speed ConverterFree speed converter for km/h, mph, knots and metres per second.Statistics Mode: Mean, Median, Std DevMean, median, standard deviation and more for a list of numbers.Student Loan / Repayment CalculatorCalculate your monthly student loan payment.Take-Home Paycheck CalculatorEstimate net pay per paycheck after federal tax and FICA.Temperature ConverterFree temperature converter for Celsius, Fahrenheit and Kelvin.Time ConverterFree time converter for seconds, minutes, hours, days, weeks and years.Traditional IRA CalculatorProject tax-deferred growth of a Traditional IRA.VA Mortgage CalculatorEstimate payments for a VA loan including the funding fee.Volume ConverterFree volume converter for litres, gallons, cups, millilitres and fluid ounces.Weight ConverterFree weight converter for kilograms, pounds, ounces, grams and stones.3D Geometry ViewerRotate seven 3D solids and calculate volume, surface area, faces, edges and vertices.3D Molecule ViewerRotate, zoom and switch between ball-and-stick and space-filling models of common molecules.4-Stroke Engine & Otto CycleWatch intake, compression, power and exhaust strokes with valves, spark and a pressure-volume diagram.AC Circuits: Resistor, Capacitor & InductorChange frequency and components and see voltage, current, phase and impedance in an AC circuit.Acid-Base LabAdd HCl or NaOH to water and watch a live pH meter and indicator colour.Acid-Base Titration SimulatorRun a full analytical titration bench: fill the burette, add titrant drop by drop or continuously, and watch the live pH meter and titration curve build as you go.Area Model Multiplication & the DistributiveSee multiplication as a rectangle, split it into four easier parts and watch the partial products add up.Atom BuilderBuild atoms from protons, neutrons and electrons and see the element, isotope and charge.Atomic Interactions: Lennard-Jones PotentialDrag two atoms and see the attractive and repulsive forces and the Lennard-Jones potential graph.Atomic Orbital VisualizerSee the shapes of s, p and d orbitals and rotate them in 3D.Balance Beam & TorqueDrag weights onto a seesaw and balance the torques on both sides.Balancing Act: Torque & SeesawBalance a plank with bricks, crates and people, learn torque, and work out a mystery mass.Balloons & Static ElectricityRub a balloon on a sweater and watch it stick to the wall, showing charge transfer and induced charge.Beam Bending & Stress SimulatorMove a load along a beam, see deflection, the bending moment diagram and whether it stays safe.Beer's Law Lab: Absorbance & ConcentrationShine light through a colored solution and see how absorbance depends on concentration, width and wavelength.Bending Light: Refraction, Reflection & PrismAim a laser at water, glass or diamond, see reflection and refraction with angles, or split white light in a prism.Bernoulli's Principle & Fluid FlowSqueeze a pipe and watch the fluid speed up while the pressure gauge drops.Blackbody Spectrum & Wien's LawChange temperature and watch the blackbody curve, peak wavelength and glow colour of a hot object.Blood Flow & Circulatory System SimulatorFollow blood from the heart through arteries, arterioles, capillaries and veins, and see how strongly flow depends on vessel radius.Bohr Model of HydrogenMake the electron jump between energy levels and see the photons absorbed and emitted.Buffer Solution SimulatorAdd acid and base to a buffer and to plain water side by side and watch which one resists pH change.Build a Nucleus: Protons, Neutrons & StabilityDrag protons and neutrons to build atoms from hydrogen to calcium and check isotopes and stability.Buoyancy & Density LabDrag objects into fluid and see when they float or sink, with the buoyant force.Calculus Grapher: Derivative & IntegralDraw a function and see its derivative, or draw the derivative and see the function.Calorimetry & Specific Heat LabDrop a hot metal into water, plot the temperatures and calculate the specific heat capacity.Capacitor Lab: BasicsChange plate area, separation and voltage to see capacitance, charge and stored energy.Car Transmission & Gear Ratio SimulatorShift through the gears of a gearbox and see the gear pair, engine rpm, wheel speed, torque and speedometer.Carbon Cycle Simulator: Reservoirs & FluxesSet emissions, deforestation and uptake rates and watch carbon flow between the atmosphere, ocean, land biosphere and fossil reserves in a real mass-balance model.Cardiac Cycle & Wiggers Diagram LabDrive the heart through atrial systole, ventricular systole and diastole, watch the valves open and close, and read a real Wiggers-style pressure graph.Catalyst & Activation EnergySee how a catalyst lowers the activation energy barrier and speeds a reaction.Cell Membrane & Osmosis SimulatorPlace a cell in a hypotonic, isotonic or hypertonic solution and watch water cross the membrane while a live graph tracks the cell's volume.Center of Mass & BalanceDrag weights on a beam and place the support so it balances at the centre of mass.Central Limit Theorem: Sampling DistributionDraw samples from any population and watch the sample means pile up into a bell curve.Charges and Fields: Electric Field & VoltagePlace positive and negative charges, drag them, and see electric field arrows and voltage colours with a live sensor.Chemical Equation BalancerPractise with 1,700+ real equations, or type your own and balance it with charges.Chemical Equilibrium SimulatorWatch the forward and reverse reactions balance and apply Le Chatelier's principle.Circuit Construction Kit: DC & AC Virtual LabBuild real circuits with batteries, bulbs, resistors, fuses, switches, wires, capacitors, inductors and household objects, then measure them with a voltmeter and an ammeter.Circuit LabWire two resistors in series or parallel and see voltage, current and power.Circular Motion & Centripetal ForceSwing a ball on a string and drag it to change the radius and speed.Climate Chemistry: CO₂ & TemperatureChange CO₂ levels and see the greenhouse effect warm the planet.Collision Lab: 2D Momentum & Kinetic EnergyCrash balls of different masses on a table and track total momentum and kinetic energy for bouncy or sticky collisions.Collision Theory SimulatorWatch molecules collide and see why only fast, well-oriented collisions react.Collisions & Momentum LabCrash two carts together and compare momentum and kinetic energy before and after.Color Theory LabBuild colour harmonies on a wheel and check text contrast against WCAG.Color Vision: How We See ColourMix red, green and blue flashlights or choose one wavelength and see how your three cone types respond.Conservation of Angular Momentum: SpinningPull a spinning skater's arms in and watch her spin speed up exactly as L = Iω is conserved, or drop one spinning disk onto another and see them lock together.Continental Drift & Plate Motion SimulatorDrag two plates and set their velocities to build convergent, divergent or transform boundaries, then watch mountains, rifts and earthquakes appear in a live cross-section.Coulomb's Law: Force Between ChargesDrag two charges along a ruler, change their size and sign, and see the electric force between them.Curve Fitting: Best-Fit Line & RegressionDrag data points and watch the best-fit line, quadratic and cubic curves and R² update.DC Motor Simulator: Torque, Speed & Back-EMFSpin a permanent-magnet DC motor against a load, watch it settle onto its torque-speed curve, and see it stall if the load is too heavy.Density Lab: Mass, Volume & Identify theWeigh mystery blocks, measure their volume by water displacement and work out the material from the density.Derivative VisualizerDrag a point along a curve and see the tangent line and the derivative graph appear.Diffraction Grating & Spectrometer LabShine light through a diffraction grating and watch the bright orders land exactly where d sinθ = mλ predicts, then try to overlap two colors' orders.Diffusion & Osmosis SimulatorSee solute and water move across a membrane and find out why water follows the higher concentration.Digital Filter Designer: Low-Pass & High-PassDesign a real RC low-pass or high-pass filter, watch its Bode magnitude plot draw live, and see exactly how much a signal is attenuated at any frequency.Digital Logic Gate SimulatorBuild circuits from AND, OR, NOT, NAND, NOR, XOR and XNOR gates, wire toggleable inputs to outputs and watch every signal propagate live, with an auto-generated truth table, Boolean expression, Karnaugh map and a NAND/NOR-only challenge mode for whatever you build.Distillation Setup LabAssemble a full distillation apparatus, fix thermometer and cooling-water mistakes, heat carefully, and read the boiling-point plateau as you separate two liquids.DNA Replication & Protein Synthesis SimulatorStep through DNA replication, transcription and translation of a short gene using real base-pairing and a genetic code table, then introduce a mutation and classify its effect.DNA Replication GameDrag the matching bases onto the unzipped DNA strand to build the copy, or type your own sequence.Doppler Effect SimulatorMove a sound source and an observer and hear how the pitch changes with speed.Double Slit & DiffractionChange wavelength and slit spacing and see the interference pattern and its intensity graph.Earthquake & Seismic Wave LaboratoryTrigger a virtual earthquake, watch P, S and surface waves radiate outward, read live seismograph traces at three stations, and triangulate the epicenter from S−P intervals.Electric Field & Charges SimulatorDrag positive and negative charges around and watch the field lines and forces react.Electric Potential & Equipotential Lines LabDrag a test point around two charges and read its potential and field live, then find where moving along an equipotential line takes zero work.Electrical Power Transformer & TransmissionStep a generator's voltage up through an ideal transformer, send the power down a resistive transmission line, and watch the current, I²R line loss and transmission efficiency all update live against the same delivered power.Electrolysis of WaterSplit water into hydrogen and oxygen and watch the bubbles collect in a 2:1 ratio.Electroplating Cell & Faraday's LawPlate an object with copper, silver, nickel, zinc or gold and calculate the mass and thickness from the current.Emission Spectrum ViewerA virtual spectrometer: 20 gases, emission, absorption and hot-solid views, an adjustable slit, UV to infrared, a hydrogen energy-level diagram and a mystery-element challenge.Energy Forms and Changes: Heat TransferHeat or cool an iron block, a brick and water, put them together and watch thermal energy flow with a live energy chart.Energy Skate ParkDrag a skater around a track and watch kinetic, potential and thermal energy trade places.Enthalpy & Activation Energy DiagramDrag the reactant, peak and product levels of an energy profile and see ΔH, Ea and the effect of a catalyst.Enzyme Activity SimulatorChange substrate, temperature, pH and inhibitors and watch the reaction rate of an enzyme.Enzyme Kinetics LaboratoryChange substrate, enzyme, temperature, pH and inhibitors, and watch a live Michaelis-Menten curve - then switch to a Lineweaver-Burk plot to estimate Vmax and Km yourself.Exoplanet Detection Lab: Transit & RadialTune a planet's size, mass and orbit and see whether the transit dip or the radial-velocity wobble is strong enough to detect above real instrument noise.Exponential Growth & Decay ExplorerCompare multiplying and adding growth for bacteria, savings, radioactive decay and viral videos, with a log scale option.Faraday's Law & Generator LabMove a magnet through a coil to light a bulb, or spin the generator and watch the induced voltage.Flower Anatomy & Pollination SimulatorClick a flower's parts to learn stigma, style, ovary, anther, filament, petal and sepal, then choose a pollination method and watch a fruit develop.Fluid Pipe Network & Pump Sizing LabSize a pipe run and a centrifugal pump, watch water flow through the pipe live, and see exactly where the pump curve and system curve meet to set the real operating flow and head.Forces & Friction SimulatorPush a block and explore Newton's laws, static and kinetic friction.Forces and Motion: Newton's Second LawPush a cart with different forces and friction and see acceleration, speed and net force.Fossil Formation & Geological Time SimulatorBury an organism and control burial depth, oxygen exposure and time to see it fossilize through compaction and mineral replacement, then read the sediment layers using relative dating.Fourier: Making WavesDrag harmonic amplitudes and watch sine waves add up to square, sawtooth and triangle waves.Fraction Builder: Compare, Add & EquivalentBuild two fractions with bars, circles and a number line, compare them, find equivalent fractions and add them.Free Fall & Motion GraphsDrop or throw an object and watch position and velocity graphs build in real time.Galvanic CellBuild a battery from two metals and watch electrons flow, with the cell voltage.Gas Laws SimulatorChange temperature, volume and particles to see pressure follow PV = nRT.Gear Train & Mechanical Advantage DesignerBuild a real two-stage compound gear train, watch the gears mesh and turn, and read off the true speed and torque the math predicts.Gear Train SimulatorDrag gears together to mesh them, then see speed and torque change through the train.Geometric TransformationsDrag a shape to translate, rotate and scale it and see the transformation matrix.Geothermal Energy & Earth's Interior SimulatorDrill a virtual geothermal well into an Earth cross-section and compute real temperature-versus-depth, extracted thermal energy and electrical power output.Gravitational Field & Escape Velocity LabPick a world, launch a rocket straight up and see whether it falls back or truly escapes, with the real field strength and escape speed live.Gravity & Orbits SandboxDrag planets, set their velocity and watch gravity build orbits, slingshots and collisions.Gravity Force LabDrag two masses and change their size to see how the gravity force depends on mass and distance.Greenhouse Effect & Earth's Energy BalanceChange the sun, reflectivity and greenhouse gases and see the surface temperature of Earth, Venus, Mars or Snowball Earth.Groundwater & Aquifer SimulatorWatch the water table rise and fall with rainfall and pumping, place a well, and see a contamination plume spread toward it through a permeable aquifer.Gyroscopic Precession LabSpin a wheel fast, hang a weight off its axle, and watch the whole axle slowly sweep around instead of falling - real torque-induced precession.Heart Pump & Cardiac CycleFollow one heartbeat through the four chambers, valves, ECG trace and blood pressure.Heat Conduction Through a Wall: Fourier's LawChange a wall's thickness, area and material, or stack layers of brick and insulation in series, and watch the heat flow and temperature gradient update live using Fourier's law.Heat Exchanger Design LabSwitch between counter-flow and parallel-flow, size a real heat exchanger, and watch the hot and cold temperature profiles run the length of the unit while effectiveness-NTU and LMTD agree on the same heat duty.Heat Exchanger Simulator: Parallel-Flow vsRun a hot and a cold fluid stream through a simple exchanger in parallel-flow or counter-flow, set the inlet temperatures, flow rates and heat transfer area, and compare the outlet temperatures, LMTD and effectiveness live.Heating Curve ExperimentAdd heat to ice and watch temperature versus time, including the flat melting and boiling plateaus.Hooke's Law: Springs and ForcesPull a spring with your mouse and see the force grow in proportion, with a force-displacement graph.Hubble's Law & Redshift LabWatch a galaxy's spectral lines redshift with distance, plot a Hubble diagram, and measure the expansion rate of the universe for yourself.Human Digestion SimulatorBuild a meal, feed it through the digestive tract, and watch real enzymes break carbohydrates, protein and fat down while a graph tracks nutrient absorption over time.Human Musculoskeletal Movement SimulatorPick a joint, activate a muscle, and watch it flex the joint against a load - with live torque, mechanical advantage and a real load-versus-force experiment.HVAC & Heat Pump SimulatorSet a thermostat and watch a heat pump cycle move heat in or out of a house.Hydraulic Press & Pascal's PrinciplePush a small piston and lift a car with a big one, and see how force, area and distance trade off.Inclined Plane SimulatorDrag the block and tilt the ramp yourself, flick it, and watch forces, speed and energy update live.Integral & Area Under CurveDrag the limits, choose the number of rectangles and compare Riemann sums with the exact area.Ionic vs Covalent BondsChange electronegativity difference and watch bonds go from covalent to polar to ionic.Isotopes & Average Atomic Mass MixerMix isotopes of chlorine, copper, boron and more and see the weighted average atomic mass on the periodic table.John Travoltage: Static Electricity & SparksRub John's foot on the carpet, collect charge, and bring his finger close to the doorknob to make a spark.Kepler's Laws of Planetary MotionChange orbit size and shape, see equal-area sectors and check the period–distance law.Kinematics Graph MatcherDrag a runner so its position-time graph matches the target line, then get a score.Kirchhoff's Rules: Multi-Loop Circuit LabChange the EMFs and resistors in a real two-loop circuit and watch all three branch currents solve live from Kirchhoff's voltage and current laws.Ladybug Motion 2D: Velocity & AccelerationDrag a ladybug around, or let it move in a line, circle or ellipse, and see its velocity and acceleration arrows change live.Le Chatelier's PrincipleChange concentration, temperature and pressure on N₂ + 3H₂ ⇌ 2NH₃ and watch the equilibrium shift.LED Circuit Designer & Resistor CalculatorBuild LED circuits with a battery, resistor, LED, switch and meters, watch real current and brightness, break them on purpose, and use 11 resistor calculators.Lens & Mirror Ray DiagramDrag the object and the focal point and watch the principal rays form the image.Light Refraction SimulatorBend a light ray between air, water, glass and diamond and find the critical angle.Limiting Reagent & Stoichiometry CalculatorType any reaction, enter grams of each reactant and find the limiting reagent and yield.Linear Equation ExplorerChange slope and intercept or drag two points to see the line, its equation and intercepts.Logistic Growth & Carrying Capacity LabRun the real logistic growth equation, add a harvesting rate, and find the maximum sustainable yield or push a population to collapse.Lunar Lander: Land Softly Physics GameFire the engine and tilt the lander to touch down softly on the pad, on the Moon, Mars or Earth.Magnet & Compass: Magnetic Field LinesDrag a bar magnet and a compass to see the magnetic field direction, strength and field lines.Magnetic Field & Compass SimulatorDrag a bar magnet around a grid of compasses and watch the field lines turn.Magnets and ElectromagnetsPower a coil with a battery, add loops, flip the current and drag a compass to see the field.Masses and Springs: Bounce LabHang masses on two springs, compare stiffness, gravity and damping, and measure the bounce period.Material Fatigue & S-N Curve LabCycle a loaded part through repeated stress, watch the waveform run, and read off the S-N curve exactly how many cycles it should survive before it fails.Mineral Identification LaboratoryRun real mineral tests — streak, Mohs hardness, luster, cleavage, density by displacement, magnetism and acid reaction — to identify an unknown specimen.Molarity & Dilution SimulatorDissolve a solute, see the concentration, and work out how much water to add to dilute it.Molecule BuilderAdd atoms and see which real molecule you have built, with a 3D model and name.Molecule Polarity SimulatorChange atom electronegativity and see bond dipoles, the net dipole and molecule polarity.Molecule ShapesDrag bonds and lone pairs onto a central atom, rotate it in 3D, and explore real molecules.Molecules and Light: Greenhouse EffectShine microwave, infrared, visible or ultraviolet light on molecules and see which absorb it and what happens.Moon Phases SimulatorMove the Moon around its orbit and see what phase looks like from Earth.Mountain Building SimulatorCompress a crustal block with adjustable plate velocity, rock strength and erosion, and watch a mountain range grow in real time cross-section, surface and stress views.Moving Man: Position, Velocity & AccelerationDrag the person along the track and watch position, velocity and acceleration graphs build.Natural Selection SimulatorWatch fur colour evolve in a bunny population as predators hunt and the environment changes.Neuron & Action Potential SimulatorStimulate a neuron and watch it fire (or fail to fire) an action potential, with a live resting → threshold → depolarization → repolarization → hyperpolarization voltage graph.Neuron Firing SimulatorStimulate a neuron and watch the action potential travel along the axon.Normal Modes: Coupled OscillatorsDrag masses on springs, excite each normal mode and see how every motion is a mix of modes.Ocean Acidification LabRaise atmospheric CO₂ and watch ocean pH fall and carbonate ions disappear, using the real carbonic acid chemistry behind ocean acidification.Ocean Acidification SimulatorSee how dissolved CO₂ lowers ocean pH and threatens shell-forming animals.Ohm's Law SimulatorChange voltage and resistance and see the current, the V = I R equation letters and a bulb brightness change.Orbital HybridizationStep through promotion, hybridisation and bonding for nine molecules with a rotating 3D hybrid-orbital picture.Orbital Motion & Gravity SimulatorLaunch a planet around a star and see circular, elliptical and escape orbits.Organic Reaction Pathways GameDrag reagents onto compounds to convert ethane, ethene, ethanol, ethanoic acid and esters, and take route challenges.Ozone Layer & UV Radiation LabRun a simplified Chapman cycle: balance ozone production against natural and CFC-driven catalytic destruction, and watch surface UV respond.Paper Chromatography & Rf ValuesSeparate the dyes of an ink on paper, choose the solvent and measure the Rf value of each dye.Pendulum Lab SimulatorExplore period, gravity and energy with a swinging pendulum.Periodic Trends ExplorerColour the periodic table by radius, electronegativity or ionisation energy and see the trends.pH Scale SimulatorTest everyday liquids and see pH, hydrogen and hydroxide ions, and acid or base.Photoelectric Effect SimulatorShine light on a metal and see when electrons are emitted, and how fast.Photosynthesis & Limiting FactorsMove the lamp, change CO₂ and temperature and count the oxygen bubbles from a pond plant.Photosynthesis Simulator: Inside theZoom inside a chloroplast and control light, CO₂, temperature and water to see the light-dependent and light-independent reactions speed up, slow down or stall.Phototropism & Gravitropism LabRotate the pot and move the light, predict which way the shoot and root will grow, then run the simulation and check your prediction.PID Control System SimulatorTune a PID controller driving a simulated DC motor toward a target speed, watch the response live, and feel what each of P, I and D actually does.PID Controller Tuning LabTune proportional, integral and derivative gains on a real first-order plant, watch the closed-loop step response redraw with a sweeping time marker, and read off the true overshoot, settling time and steady-state error.Pipe Flow & Reynolds Number SimulatorPick a fluid and a pipe, set the flow rate, and watch whether it flows in smooth layers or chaotic turbulence.Plant Genetics & Mendelian InheritanceCross two parent plants for flower colour, seed shape or height, build the Punnett square, then breed real offspring and compare the ratio to Mendel's theory.Plant Hormone SimulatorDial up auxin, gibberellin, cytokinin, ethylene and ABA and watch a plant bend toward light, stretch taller, branch out, ripen fruit or drop its leaves.Plant Nutrient Deficiency LaboratoryDiagnose a mystery plant's hidden nutrient deficiency from real symptom patterns - which leaves are affected and how - then submit your answer.Plant Transpiration LaboratoryControl humidity, temperature, wind and stomatal aperture in a sealed chamber, zoom on the stomata, and measure the transpiration rate live.Plant Water Transport: Xylem SimulatorFollow water from root to leaf through the xylem, and see how transpiration, root pressure and vessel width set the water's speed and pressure.Plate Tectonics & EarthquakesWatch plates collide, spread apart and slide past each other to build volcanoes, ridges and earthquakes.Plinko Probability: Galton BoardDrop balls through pegs and watch the bell-shaped binomial distribution build, with the theory curve.Polarization of Light: Malus's Law LabTurn a polarizing filter and watch the transmitted light dim exactly as I = I0 cos²θ predicts, then bring light back through crossed filters with a third one.Precipitation Reactions LabMix real quantities of ionic solutions, watch a staged nucleation-and-settling animation, check Q against Ksp, then filter, weigh and calculate percent yield.Predator-Prey Population SimulatorWatch rabbit and fox populations rise and fall with the Lotka-Volterra model.Probability LabFlip coins and roll dice thousands of times and compare results with theory.Projectile Data Lab: Air Resistance & TargetFire golf balls, pumpkins and pianos with and without air resistance and collect a table of ranges.Projectile Motion SimulatorLaunch a projectile and watch its path, range and max height change live.Pulley System SimulatorPull the rope, see how more rope strands cut the force you need but lengthen the pull.Punnett Square CalculatorCross two parents and get genotype and phenotype ratios, for one trait or two.Quadratic Function ExplorerDrag a, b and c to see the parabola, roots, vertex and discriminant change.Quantum Coin TossToss a quantum coin, put it in superposition, measure it and see interference bring it back to heads.Quantum Measurement: Stern-Gerlach ExperimentSend spin particles through analyzers along Z and X and see how measurement changes the state.Quantum Wave InterferenceFire photons, electrons or neutrons one at a time and watch the wave pattern build dot by dot.Radioactive Decay & Half-Life SimulatorWatch hundreds of unstable atoms decay at random and compare the count with the half-life curve.RC Circuit & Capacitor SimulatorCharge and discharge a capacitor through a resistor 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removalIsometric, Dot & Graph Grid Paper GeneratorMake printable isometric, dot, graph, hex and engineering grid paper in any size and spacing as SVG or 300 dpi PNGLaser & CNC Nesting Tool — Pack Parts ontoPack the parts in a DXF or SVG onto sheets of your size with quantities, spacing and rotationLaser Cutter SVG & DXF CleanerFix messy cutting files: join loose lines, remove double cuts, close gaps and order cuts inside-outLayer Height & Nozzle Settings CalculatorLayer height, line width, walls, first layer, speed limits and Z-step-friendly layer heightsOnline DXF Viewer with Measure Tool, Layers &View a DXF file in your browser: zoom, pan, toggle layers, measure with snapping and see shape propertiesOnline STL Slicer Preview — Layers, PrintSlice an STL into layers, scrub through them and estimate time, filament and costOnshape Export Format Helper — Which FormatPick the right Onshape export format and settings for printing, laser, CAM, AR, sharingOnshape FeatureScript Snippet Library & CheatCopy-paste FeatureScript snippets: parameters, sketches, booleans, patterns, queriesOnshape Sketch Constraints, Shortcuts &Understand sketch constraints, fix over-defined sketches, and learn good Onshape habitsOnshape to Slicer 3D Printing Workflow GuideStep-by-step Onshape → STL → slicer checklist for Orca, Bambu, Prusa and CuraPDF Drawing to DXF / SVG Vector ExtractorExtract the real vector lines and curves from a PDF drawing into DXF or SVG at true scalePLY / OFF / AMF / GLB / FBX / 3DS to STLConvert PLY, OFF, AMF, GLB, glTF, FBX and 3DS files to STL for printingResin 3D Print Calculator — Exposure, Time &Print time, resin volume & cost, exposure time from cure curve, pixel sizeSTEP / IGES to OBJ & GLB ConverterCAD solids to OBJ or GLB for AR, web 3D, Blender and UnitySTEP / STP to STL ConverterConvert STEP, STP & IGES CAD files to STL, OBJ, 3MF — free, in your browserSTL Boolean ToolMerge, cut or intersect two 3D models, or drill holes with built-in primitivesSTL Cross-Section to DXF / SVG OutlineCut a 3D model with a plane and export the section outline, area and perimeter, or all layers for laser-cut stacksSTL Hollow Tool — Hollow Out Models & SaveHollow an STL with a set wall thickness and a drain hole, see resin savedSTL Merge, Split & Cut ToolMerge STLs onto one plate, split shells apart, or cut a model with a planeSTL Overhang & Support CheckerSee which faces need supports at your slicer's overhang angleSTL Repair Tool & Mesh CheckerFind and fix holes, flipped normals and non-manifold edges in STL filesSTL Scale, Rotate, Mirror & Unit Fix ToolFix 'model is 25.4× too big', rotate, mirror and resize STL filesSTL Simplifier & SmootherReduce the triangle count of a heavy STL/OBJ or smooth a rough scan without shrinking itSTL to 2D Drawing — Top, Front & Side ViewsTurn a 3D model into a third-angle three-view outline sheet with overall dimensions, as SVG or DXFSTL to STEP ConverterTurn an STL mesh into a STEP B-rep solid with planar facesSTL Wall Thickness CheckerFind walls that are too thin to print and see them highlighted in red on the modelSTL Weight, Centre of Mass & Moment ofExact volume, mass, centre of gravity and inertia tensor of any STL, OBJ, 3MF or STEP modelSTL ⇄ OBJ 3D Model ConverterConvert STL, OBJ, PLY, 3MF, AMF, GLB — batch, with unit fixSVG / DXF Path Offset & Kerf Compensation ToolGrow, shrink or kerf-compensate every closed path in an SVG or DXF so laser and CNC parts finish at the drawn sizeSVG to DXF Converter with Unit & Scale ControlExact-size SVG to DXF: pick source units, scale to a width, layers by colour2D Truss Solver — Member Forces, Reactions &Solve pin-jointed trusses: tension/compression in every member, support reactions and displacements, with a force diagramBeam Deflection & Stress CalculatorDeflection, reactions, bending moment and stress for supported and cantilever beamsBolt Circle & Hole Pattern CoordinateHole coordinates for bolt circles, rows and grids with DXF, SVG and G-code exportBolt Torque, Preload & Strength CalculatorTightening torque, clamp force, proof load and design resistances for M3–M36 bolts by property classCNC Machining Cost & Time EstimatorEstimate CNC milling time, cost per part and price vs quantityComposite Section Moment of Inertia CalculatorCentroid, moment of inertia and section modulus of any shape built from rectangles, circles, triangles, semicircles and holesCompression Spring Design CalculatorSpring rate, stress, solid height, buckling and number of coils for compression springsEngineering Unit Converter with UnitConvert any engineering unit or compound expression (lbf*ft to N*m, psi to MPa, kg*m/s^2 to N) with dimension checkingFeet & Inches CalculatorConstruction calculator for feet-inch-fraction arithmetic and dividing a length into equal spacesFillet Weld Size & Strength CalculatorCapacity of fillet welds from leg size and length: AISC ASD/LRFD and Eurocode 3, with minimum and maximum sizeGD&T Symbols Reference & Feature ControlLearn the 14 GD&T symbols, tolerance zones and modifiers, and build a feature control frame to copy or downloadGear Calculator & Involute Gear SVG/DXF/STLModule, pitch, centre distance, ratio — and export gears as SVG, DXF or STLHeat Sink & Thermal Resistance CalculatorRequired heat-sink thermal resistance, finned heat-sink estimate, interface conduction and regulator heatISO 286 Fit & Tolerance CalculatorLimits and fits for any size: hole/shaft deviations, clearance or interferenceKeyway & Parallel Key Size Chart and TorqueLook up key width, height and keyway depths for any shaft diameter and check the torque capacityLaser Cutting Cost & Time EstimatorUpload SVG/DXF to measure cut length and pierces; get time, material and priceMaterial Weight CalculatorWeight from dimensions and density for plates, bars, tubes, pipes and moremm ⇄ Inch Fraction & Tolerance ConverterMillimetres to inch fractions with tolerance limits and a batch listMohr's Circle Calculator — Principal StressesPrincipal stresses, maximum shear, von Mises and Tresca from σx, σy and τxy, with the circle drawnO-Ring Groove & Gland Design CalculatorSize an O-ring groove: gland depth, width, squeeze, fill and stretch for static, radial and dynamic sealsPipe Flow & Pressure Drop CalculatorVelocity, Reynolds number, friction factor, head loss, pressure drop and pump power for pipe flowSecond Moment of Area & Section PropertiesArea, centroid, Ix, Iy, section modulus, radius of gyration for common sectionsSheet Metal Bend Allowance & K-FactorBend allowance, bend deduction, setback, flat length and K-factor from a test bendSurface Finish Converter & ChartConvert Ra, µin, RMS and ISO N grades, with typical roughness by process and by applicationThread & Fastener Chart — Tap DrillMetric & imperial thread data: tap drill, clearance holes, head sizes, torqueTolerance Stack-Up Calculator1D tolerance stack-up with worst-case, RSS, Monte-Carlo simulation, contributors and out-of-spec prediction3D Print Tolerance & Clearance Test GeneratorGenerate a numbered test plate with holes of increasing clearance and matching pegs to dial in your printer's fit3D Print Troubleshooting Guide — FixPick a symptom and get the likely causes and exact fixes, ranked from most to least likely3D Printable Gear Generator — Spur, Helical &Generate true involute spur, helical and herringbone gears with bore, keyway, hub and a meshing partner as STL3D Text & QR Code STL GeneratorMake 3D text signs, keychains and scannable QR code plates as STL3D-Printable Box with Lid GeneratorParametric box and friction-fit lid STL with rounded corners and clearance3D-Printable Screw Thread GeneratorGenerate metric (ISO) and trapezoidal threads: bolts, nuts and threaded rods as watertight STLArduino, ESP32, Pico & ESP8266 PinoutSearchable pin functions, PWM/ADC/I²C/SPI pins and boot-strapping warnings for popular boardsBearing, Magnet & Nut Pocket Size CalculatorPocket and hole sizes for bearings, magnets, nuts and screw heads by printer and fit, with a test couponExtruder E-Steps, Rotation Distance & FlowCalculate new e-steps, Klipper rotation_distance, flow multiplier and maximum print speed from simple measurementsFilament Chooser — PLA vs PETG vs ABS vs ASATell it what the part needs and see the best-matching 3D printing materials with settings and trade-offsGridfinity Bin & Baseplate GeneratorGenerate custom Gridfinity bins and baseplates as STL — any size, dividers, scoopGyroid Lattice GeneratorGenerate printable gyroid, Schwarz-P and diamond lattice blocks with adjustable cell size and densityHeightmap / Image to STL Relief GeneratorConvert a grayscale image or terrain heightmap into a 3D-printable relief STLKeychain & Name Tag STL MakerCustom keychains and name tags with raised or inlay text, border and key-ring tab — STL / 3MFKnob & Thumb Screw Generator STLDesign fluted, knurled or lobed knobs with round, D-shaft or screw hole with hex nut trapLaser Cut Box GeneratorFinger-joint box and tray plans as SVG/DXF, with kerf and a living-hinge panelLaser Power/Speed Test Grid, Kerf Test &Generate GRBL G-code test grids, kerf/fit test files and read which materials are safe to laserLithophane Generator — Photo to 3D PrintableTurn a photo into a 3D-printable lithophane STL with backlit previewMouse Ears Generator — Anti-Warp Pads for STLAdd thin disc pads to the corners of a model to stop warping, without a messy brimParametric Bracket, Standoff & SpacerGenerate L-brackets, standoffs, spacers, washers and mounting plates as STLPCB Trace Width, Via Current & MicrostripIPC-2221 trace width and current, via capacity, resistance, voltage drop and microstrip impedancePegboard Panel & Peg Hook GeneratorPrint your own pegboard panels and two-peg hooks to custom sizesPrimitive Shapes STL Generator — CubeCreate exact test shapes — boxes, cylinders, tubes, spheres, tori, pyramids, wedges and more — as STLPrint-in-Place Hinge Generator & Snap-FitGenerate a working print-in-place hinge STL and calculate snap-fit cantilever deflection and forceStepper Steps per mm, Belt Length & PulleySteps per mm for belts and lead screws, belt length and centre distance, speed and torqueSVG to STL ExtruderExtrude SVG shapes into a printable STL with holes, base plate and keyring option10-Minute Abs WorkoutCore, lower abs and standing abs workouts with a 3D coach12-Week Workout ProgramsThree full 12-week programs with automatic progression and deload weeks7-Day & 30-Day Fitness Challenge TrackerPush-up, squat, plank and more: daily targets, calendar and streak7-Minute WorkoutThe classic 12-exercise 7-minute workout with a 3D coach and voiceAMRAP & EMOM Workout TimerAMRAP, EMOM and For Time with voice, round counter and movementsArm Workout No EquipmentTriceps, biceps and shoulders at home with a 3D coachBack Workout at HomeBodyweight, dumbbell and band back workouts with a 3D coachBarbell Plate CalculatorWhich plates to load on each side, with a visual barBasketball Shot CounterCounts your shooting motions and checks your follow-throughBeginner Workout PlansSix step-by-step plans: full body, push-ups, squats, core, 5K and mobilityBiceps Curl CounterCounts every biceps curl with your camera and tells you to curl higherBoxing & MMA Round TimerRounds with bell, 10-second warning clap and voice, presets for boxing and MMABoxing Punch CounterCounts every jab, cross and hook with your cameraCalories Burned CalculatorCalories burned by 37 activities, using MET values and your weightCamera Burpee CounterCounts burpees when you drop to the floor and stand back upCamera High Knees & Mountain Climber CounterCounts high knees or mountain climbers with the cameraCamera Jump Rope CounterCounts your jumps with the camera, with or without a ropeCamera Jumping Jack CounterCounts jumping jacks with your camera and says each numberCamera Lunge CounterCounts lunges with the camera and checks your front kneeCamera Pull-Up CounterCounts pull-ups when your chin clears the bar, any camera angleCamera Push-Up CounterYour camera counts every push-up and checks your form, from any angleCamera Sit-Up & Crunch CounterCounts sit-ups or crunches with your camera, from any angleCamera Squat CounterCounts your squats with the camera and checks depth, any angleCamera Workout ModeChain squats, push-ups, planks and more: the camera counts and the voice coachesChest & Shoulder Workout at HomePush-up variations and dumbbell presses with a 3D coachCricket Batting & Bowling AnalyzerBatting and bowling actions: arm speed, elbow, front knee, head stabilityCustom Workout Builder with Voice CoachChoose from 120+ exercises, set reps & sets, then follow the voiceCycling Calculators: Speed, Power, Gears & FTPSpeed/time/distance, watts needed, gear ratio and FTP zones in one pageDeload & Recovery Readiness AdvisorDaily readiness score: train hard, go light, rest or deloadDesk Exercise Reminder for Office WorkersMovement break reminders with 1-5 minute voice-guided desk routinesDesk Posture CheckerWebcam watches your posture and reminds you to sit up and stretchDiet & Meal Planner with Shopping ListCalorie-matched meal plans with macros and a shopping listDOTS & Wilks CalculatorPowerlifting score from squat, bench, deadlift and body weightDumbbell Full Body WorkoutFull body, upper body and lower body dumbbell workoutsDynamic Warm-Up Routine5-minute warm-ups for any workout, legs or upper bodyExercise Library with Animations170 exercises with animated demos, muscles and how-to cuesExercise Timer with VoiceType your exercises, set work and rest, and a voice calls each one outFFMI CalculatorLean mass, fat mass and FFMI with a muscularity ratingFitness Blog & Guides9 practical fitness guides: push-ups, reps, protein, stretching and moreFitness Test ScorecardRate your fitness by age and sex: push-ups, sit-ups, plank and 1.5-mile runFitness Tools HubFind the right fitness tool by goal: lose fat, get stronger, stretch, trackFood Calorie & Macro Lookup + Daily Diary150+ foods with calories, protein, carbs, fat and a daily food diaryGentle Rehab Routines: Back, Knee, Shoulder &Voice-guided gentle routines with 3D demos and clear safety notesGlute Bridge CounterCounts every glute bridge and prompts you to lift higherGlute Workout at HomeBridges, kicks and thrusts with a 3D demo and voice coachGolf Swing AnalyzerRecord or load a swing: tempo, rotation, head movement, compare two swingsGPS Run Tracker with MapTrack runs, walks and rides: distance, pace, splits, route map, GPX exportHeart Rate Zones CalculatorFind your 5 training zones and max heart rate by ageHip Hinge & Deadlift CounterCounts deadlifts, good mornings and hip hingesIdeal Weight CalculatorDevine, Robinson, Miller & Hamwi formulas plus a healthy BMI rangeInteractive Muscle MapTap a muscle to see what it does and the best exercises for itKick CounterCounts front, side and roundhouse kicks with your cameraKids PE Challenges & Class ScoreboardAnimal workouts, brain breaks and 60-second challenges with a scoreboardLateral & Front Raise CounterCounts every lateral or front raise to shoulder heightLeft-Right Balance & Symmetry TestCompare your left and right side: balance, squat, shoulders, push-upsLeg Day at HomeQuads, hamstrings, glutes and calves with a 3D coachLeg Raise CounterCounts lying leg raises and checks you lift toward verticalMacro CalculatorDaily calories and protein, carb and fat grams for your goalMeditation Timer with Guided Breathing & Bells3-30 minute sessions: guided breathing, body scan or silent with bells and ambient soundsMobility Screening TestDeep squat, toe touch, overhead reach and lunge, scored 0-3Morning Energy Workout5 or 10 minute wake-up workouts, including a no-jumping optionOne-Rep Max CalculatorEstimate your max lift from any set, with a training-weights tablePace Band & Split CalculatorPrintable splits for any race: even, negative or fast-start strategyPedometer for Your PhoneCounts steps with your phone's motion sensors, with distance and caloriesPersonal Records BoardAll your best lifts, rep records and run times in one placePlank Timer with Form CheckTimes your plank and warns you when your hips sag or liftProgress Photos with Before/After SliderPrivate photo timeline with a drag-to-compare before and after sliderPronunciation PracticeHear a model voice, say it yourself and get a word-by-word scoreProtein Intake CalculatorHow many grams of protein you need per day and per mealPush-Up Coach with VoicePick reps, sets & speed, then a voice says Down, Up, 1, 2, 3Quiet Cardio WorkoutApartment-friendly, low-impact cardio with a 3D coachRace Time Predictor & Training PacesPredict 5K to marathon times and get easy, tempo and interval pacesRep & Set TrackerLog weight, reps and sets, with an automatic rest timerRest Timer with VoiceRest timer between sets with voice alerts and auto-restartRun/Walk Interval Timer & Couch to 5KVoice-guided run/walk intervals: Couch to 5K, custom and speed playRunning Cadence & Music BPM CalculatorSteps per minute for your pace, and the pace for a song's BPMSenior Chair Exercises & Balance TestsChair workouts for older adults plus 30-second chair stand and balance testsShoulder Press CounterCounts every overhead press and checks you lock outSteps to Distance CalculatorConvert steps to km/miles, time and calories (and back)Strength Program CalculatorWeights for popular strength programs from your 1RMStrength Standards CalculatorHow strong are you? Bench, squat, deadlift levels by body weightStrength Workout for RunnersSingle-leg strength, glutes and core to run strongerStretch Routine Guide8 guided stretching routines with timers, sides and breathing cuesStretching Guides with Animations18 stretches with animated demos, steps, benefits and hold timesSweat Rate CalculatorHow much you sweat per hour and how much to drinkSwimming Calculators: Pace, Laps, Calories &Pace per 100 m, lap converter, calories burned and critical swim speedTennis Stroke AnalyzerForehand, backhand and serve: speed, rotation, knee bend, compare strokesText Reader with Highlighted WordsRead any text aloud and follow the highlighted wordTriceps Dip CounterCounts chair or bar dips from any angleVO2 Max CalculatorCooper, 1.5-mile, Rockport walk and resting heart rate methodsVoice CounterA voice counts out loud for you: up, down, by 2s, 5s or 10sWaist-to-Height & Waist-to-Hip RatioHealth-risk ratios from your waist, hip and heightWall Sit TimerTimes your wall sit and warns when you slide up or too lowWarm-Up Sets CalculatorRamp-up sets to your working weight, rounded to platesWeekly Workout PlannerChoose your days, goal and equipment, get a full week of workoutsWeight & Body Measurements TrackerTrack weight, waist, chest, hips, arms with charts and a goal lineWeight Loss Timeline CalculatorHow long to reach your goal weight, with a date and weekly projectionWorkout GeneratorPick muscles, equipment and minutes, get a full workout with animationsWorkout Log & History TrackerStreaks, a 20-week heat map and a log of every workoutYoga Flow BuilderBuild your own yoga flow from 50+ poses and let a voice guide youYoga Pose CheckerCamera checks your yoga pose joint by joint and tells you what to fixBrain Type Quiz — Fast Thinker, OverthinkerA short quiz that reveals your brain type with a shareable personality cardBroke Score — How Broke Are You Really?A funny but real 0-100% broke score from your income, spending and savingsCategory Rush GameName something in the category with a random letterClean Jokes TellerThousands of clean jokes with a punchline revealCompare Yourself to the WorldSee your estimated income and sleep percentile vs the world, based on cited averagesDigital Life Report — Brain Performance ScoreIn-page typing and reaction tests plus your habits, combined into one Brain Performance ScoreFive in a RowGomoku vs computer or a friend on one screenFocus Score Test — Real Timed Attention TestA real in-browser go/no-go attention test with a measured, timed scoreFuture Net Worth Simulator — Spend vs InvestCompare two real compound-interest projections: keep spending vs start investingGirls' Night Party GamesMost likely to... and Spill the Beans promptsGroup Story BuilderBuild a silly story one sentence at a timeHousie Tambola Number CallerNumber caller and ticket generator for HousieHow Well Do You Know Me?Friend and bride/groom quiz questionsLife in Numbers — How Much of Your LifeSee how many years you've spent asleep and on your phone, from your own numbersMafia Role DealerDeal secret Mafia roles and read the narrator scriptMancalaClassic Mancala vs computer or two playersMove-Out Readiness ScoreA real 50/30/20-style affordability score for moving out on your ownNever Have I Ever Questions1,200+ clean Never Have I Ever promptsOne Sentence About Your LifeA few quick picks generate one blunt, reflective sentence about where you're atOverthinking Score — Rumination Self-CheckA short self-report quiz based on real rumination-scale concepts, with a percentile scoreParty Bingo CardsBridal, baby shower, mehndi, birthday and girls' night bingoPass the Bomb GameHidden-timer party game: name one and pass it onPictionary Word GeneratorEasy, medium and hard drawing words with a timerRapid Fire Questions10 quick questions, 5 seconds eachRarity Score — How Rare Are You?An 8-question quiz that reveals how rare your everyday habits really areRiddles with AnswersBrain-teasing riddles, answer hidden until you tapRideshare Driver Profit Reality CheckReal effective hourly take-home after true vehicle costs, vs local minimum wageSilly Would You RatherAbsurd dilemmas with a group vote counterSleep Debt Calculator — Real Nights OwedReal arithmetic on how many full nights of sleep you're behind onSmarter Than Average QuizA 6-question logic trick-quiz with a percentile score vs a stated averageSticks GameTake 1 to 3 sticks; last stick losesSubscription Cost Reality CheckAdd your subscriptions and see the real annual total plus relatable comparisonsTeam Trivia BattleTeam quiz night with 4,600+ questionsText Personality AnalyzerPaste your own text for a heuristic style read — confident but impatient? Curious and detailed?Time Wasted on Phone — Lifetime CalculatorReal arithmetic on how many years of your life you'll spend on your phoneTongue Twister Challenge200+ tongue twisters to say three times fastTruth or Dare GeneratorClean truth and dare prompts, no repeatsTwo Truths and a LieTopic prompts and a score of who fooled the groupUndercover Word GameSpy word party game, pass one phone aroundWheel of NamesAdd names, spin the wheel and pick a fair random winner.Where Should You Live? Personality ArchetypeA fun quiz matching your preferences to a place archetype — not real relocation adviceWho Am I? Guessing GameHeads-up charades with a timer, 400 wordsWould You Rather Questions4,500 would-you-rather dilemmas3-Way Loan Comparison ToolCompare up to three real loan offers side by side — payment, total interest, and total cost — so you can see instantly which offer actually wins.401 CalculatorProject your 401(k) balance including employer match.529 College Savings Plan CalculatorProject tax-advantaged 529 plan growth toward a future college cost goal.Amortization CalculatorSee exactly how each payment splits between principal and interest over the life of your loan.Annuity CalculatorProject the future value of a stream of regular payments.Annuity Payout CalculatorConvert a lump sum into a guaranteed monthly payout.APR CalculatorSee the true annual cost of a loan once lender fees are blended in.Area ConverterFree area converter for square metres, square feet, acres and hectares.Auto Lease CalculatorEstimate your monthly lease payment using the money factor method.Auto Loan CalculatorCalculate your monthly car payment including trade-in and sales tax.Average Return CalculatorCalculate the compound annual growth rate between two values.Basic CalculatorA simple online calculator for everyday sums.Boat Loan CalculatorCalculate your monthly payment on a boat loan.Bond CalculatorEstimate a bond's price given face value, coupon and market yield.Budget CalculatorSplit your take-home income into needs, wants, and savings.Business Loan CalculatorCalculate monthly payment on a business loan including origination fee.Cash Back or Low Interest CalculatorCompare a manufacturer cash-back offer vs. a promotional low APR.CD CalculatorProject the maturity value of a Certificate of Deposit.College Cost CalculatorProject the future cost of college given inflation and years until enrollment.Commission CalculatorCalculate commission earned on a sale.Complex Number CalculatorCalculate with complex numbers online.Credit Card Payoff CalculatorSee how long a fixed monthly payment takes to clear a credit card balance.Currency CalculatorConvert between currencies using a manual exchange rate.Data Storage ConverterFree data storage converter for bytes, kilobytes, megabytes, gigabytes and terabytes.Debt Consolidation CalculatorCompare your current blended debt payments vs. one consolidation loan.Debt Snowball vs. Avalanche PlannerEnter every debt you owe and see the exact month-by-month order to pay them off two ways — Snowball (smallest balance first) and Avalanche (highest interest first) — with total interest for each strategy compared side by side.Debt-to-Income Ratio CalculatorLenders use DTI to judge how much of your income already goes to debt.Depreciation CalculatorCalculate straight-line depreciation for an asset.Down Payment CalculatorCalculate your down payment, loan amount, and whether you'll owe PMI.Emergency Fund CalculatorCalculate how much you need saved to cover 3–6 months of essential expenses.Energy ConverterFree energy converter for joules, calories, kilowatt-hours and BTU.Equation SolverSolve linear, quadratic and cubic equations and 2x2 systems.Estate Tax CalculatorEstimate federal estate tax owed above the exemption threshold.FHA Loan CalculatorEstimate payments including upfront and monthly mortgage insurance premium (MIP).Finance CalculatorCompound interest, loan and other finance sums in the calculator.Full Amortization Schedule GeneratorGenerate a complete month-by-month payment schedule for any loan — export it to CSV and see the balance payoff curve. This produces hundreds of exact calculated rows a chatbot cannot compute or hand you as a real file.Future Value CalculatorWhat will today's money be worth in the future?General Finance CalculatorTime-Value-of-Money: solve for Future Value given PV, PMT, rate and periods.HELOC CalculatorEstimate your available credit line and interest-only draw payment.Home Equity Loan CalculatorSee your available equity and estimated fixed loan payment.Hourly to Salary CalculatorConvert an hourly wage into annual, monthly and weekly salary equivalents.House Affordability CalculatorEstimate the maximum home price you can comfortably afford using the 28/36 rule.Inflation CalculatorSee what a past dollar amount is worth today (or in the future) after inflation.Interest Rate CalculatorSolve for the interest rate given a starting and ending value.Investment Interest CalculatorProject the growth of a lump-sum investment with compounding.Investment Portfolio RebalancerEnter your current holdings and target allocation — get the exact dollar amount to buy or sell in each asset class to rebalance, plus a live pie chart.IRR CalculatorCalculate the Internal Rate of Return for an initial investment and 3 years of cash flow.Job Offer Comparison ToolCompare two job offers beyond base salary — bonus, PTO value, benefits, and cost-of-living — to see which is actually worth more.Lease CalculatorEstimate a general equipment or asset lease payment.Length ConverterFree length converter for meters, feet, inches, kilometres and miles.Live Currency ConverterFetches live exchange rates from our currency API right now — not a guessed or outdated number a language model would make up.Marriage Tax CalculatorCompare combined tax filing jointly vs. as two single filers.Matrix CalculatorDeterminant, inverse and multiplication for matrices.Mortgage Extra-Payment "What-If" SimulatorDrag a live slider to see, in real time, exactly how many years and how much interest an extra monthly payment saves on your mortgage.Mortgage Payoff CalculatorSee how much time and interest an extra monthly payment can save.Mutual Fund CalculatorProject growth of a mutual fund investment including expense ratio drag.Net Worth TrackerTrack everything you own vs. everything you owe. Saves your entries in this browser so you can update it over time and watch the trend — something a stateless chatbot reply can never remember for you.Pay Stub GeneratorGenerate and print a real itemized pay stub with gross pay, tax withholding, deductions, and net pay — a formatted document, not just a spoken number.Payback Period CalculatorFind out how long it takes an investment to pay for itself.Payment CalculatorStandard loan payment calculator for any purpose.Pension CalculatorEstimate an annual defined-benefit pension payout.Personal Loan CalculatorCalculate your monthly payment on an unsecured personal loan.Present Value CalculatorWhat is a future sum of money worth today?Pressure ConverterFree pressure converter for pascal, bar, PSI, atmospheres and mmHg.Programmer CalculatorConvert and calculate in hex, binary, octal and decimal.Real Estate Appreciation CalculatorProject a property's future value and equity growth.Refinance CalculatorFind your breakeven point when refinancing to a new rate or term.Rent CalculatorEstimate a comfortable monthly rent budget using the classic 30% of gross income rule.Rental Property CalculatorEstimate cash flow, cap rate and cash-on-cash return for an investment property.Retirement CalculatorProject your retirement nest egg based on current savings and contributions.Retirement Withdrawal SimulatorSimulate spending down a retirement portfolio year by year with inflation-adjusted withdrawals and market growth — and see the exact year the money runs out, if ever.RMD CalculatorCalculate your Required Minimum Distribution using the IRS Uniform Lifetime Table.ROI CalculatorCalculate a simple return on investment percentage.Roth IRA CalculatorProject tax-free growth of a Roth IRA.Sales Tax CalculatorCalculate sales tax and total price, or back it out from a total.Savings CalculatorSee how a monthly savings habit grows over time.Self-Employment Tax CalculatorCalculate Social Security + Medicare tax owed on freelance/1099 net income.Simple Interest CalculatorInterest calculated only on the original principal — no compounding.Social Security CalculatorRough estimate of your monthly benefit based on average indexed earnings and claiming age.Speed ConverterFree speed converter for km/h, mph, knots and metres per second.Statistics Mode: Mean, Median, Std DevMean, median, standard deviation and more for a list of numbers.Student Loan / Repayment CalculatorCalculate your monthly student loan payment.Take-Home Paycheck CalculatorEstimate net pay per paycheck after federal tax and FICA.Temperature ConverterFree temperature converter for Celsius, Fahrenheit and Kelvin.Time ConverterFree time converter for seconds, minutes, hours, days, weeks and years.Traditional IRA CalculatorProject tax-deferred growth of a Traditional IRA.VA Mortgage CalculatorEstimate payments for a VA loan including the funding fee.Volume ConverterFree volume converter for litres, gallons, cups, millilitres and fluid ounces.Weight ConverterFree weight converter for kilograms, pounds, ounces, grams and stones.3D Geometry ViewerRotate seven 3D solids and calculate volume, surface area, faces, edges and vertices.3D Molecule ViewerRotate, zoom and switch between ball-and-stick and space-filling models of common molecules.4-Stroke Engine & Otto CycleWatch intake, compression, power and exhaust strokes with valves, spark and a pressure-volume diagram.AC Circuits: Resistor, Capacitor & InductorChange frequency and components and see voltage, current, phase and impedance in an AC circuit.Acid-Base LabAdd HCl or NaOH to water and watch a live pH meter and indicator colour.Acid-Base Titration SimulatorRun a full analytical titration bench: fill the burette, add titrant drop by drop or continuously, and watch the live pH meter and titration curve build as you go.Area Model Multiplication & the DistributiveSee multiplication as a rectangle, split it into four easier parts and watch the partial products add up.Atom BuilderBuild atoms from protons, neutrons and electrons and see the element, isotope and charge.Atomic Interactions: Lennard-Jones PotentialDrag two atoms and see the attractive and repulsive forces and the Lennard-Jones potential graph.Atomic Orbital VisualizerSee the shapes of s, p and d orbitals and rotate them in 3D.Balance Beam & TorqueDrag weights onto a seesaw and balance the torques on both sides.Balancing Act: Torque & SeesawBalance a plank with bricks, crates and people, learn torque, and work out a mystery mass.Balloons & Static ElectricityRub a balloon on a sweater and watch it stick to the wall, showing charge transfer and induced charge.Beam Bending & Stress SimulatorMove a load along a beam, see deflection, the bending moment diagram and whether it stays safe.Beer's Law Lab: Absorbance & ConcentrationShine light through a colored solution and see how absorbance depends on concentration, width and wavelength.Bending Light: Refraction, Reflection & PrismAim a laser at water, glass or diamond, see reflection and refraction with angles, or split white light in a prism.Bernoulli's Principle & Fluid FlowSqueeze a pipe and watch the fluid speed up while the pressure gauge drops.Blackbody Spectrum & Wien's LawChange temperature and watch the blackbody curve, peak wavelength and glow colour of a hot object.Blood Flow & Circulatory System SimulatorFollow blood from the heart through arteries, arterioles, capillaries and veins, and see how strongly flow depends on vessel radius.Bohr Model of HydrogenMake the electron jump between energy levels and see the photons absorbed and emitted.Buffer Solution SimulatorAdd acid and base to a buffer and to plain water side by side and watch which one resists pH change.Build a Nucleus: Protons, Neutrons & StabilityDrag protons and neutrons to build atoms from hydrogen to calcium and check isotopes and stability.Buoyancy & Density LabDrag objects into fluid and see when they float or sink, with the buoyant force.Calculus Grapher: Derivative & IntegralDraw a function and see its derivative, or draw the derivative and see the function.Calorimetry & Specific Heat LabDrop a hot metal into water, plot the temperatures and calculate the specific heat capacity.Capacitor Lab: BasicsChange plate area, separation and voltage to see capacitance, charge and stored energy.Car Transmission & Gear Ratio SimulatorShift through the gears of a gearbox and see the gear pair, engine rpm, wheel speed, torque and speedometer.Carbon Cycle Simulator: Reservoirs & FluxesSet emissions, deforestation and uptake rates and watch carbon flow between the atmosphere, ocean, land biosphere and fossil reserves in a real mass-balance model.Cardiac Cycle & Wiggers Diagram LabDrive the heart through atrial systole, ventricular systole and diastole, watch the valves open and close, and read a real Wiggers-style pressure graph.Catalyst & Activation EnergySee how a catalyst lowers the activation energy barrier and speeds a reaction.Cell Membrane & Osmosis SimulatorPlace a cell in a hypotonic, isotonic or hypertonic solution and watch water cross the membrane while a live graph tracks the cell's volume.Center of Mass & BalanceDrag weights on a beam and place the support so it balances at the centre of mass.Central Limit Theorem: Sampling DistributionDraw samples from any population and watch the sample means pile up into a bell curve.Charges and Fields: Electric Field & VoltagePlace positive and negative charges, drag them, and see electric field arrows and voltage colours with a live sensor.Chemical Equation BalancerPractise with 1,700+ real equations, or type your own and balance it with charges.Chemical Equilibrium SimulatorWatch the forward and reverse reactions balance and apply Le Chatelier's principle.Circuit Construction Kit: DC & AC Virtual LabBuild real circuits with batteries, bulbs, resistors, fuses, switches, wires, capacitors, inductors and household objects, then measure them with a voltmeter and an ammeter.Circuit LabWire two resistors in series or parallel and see voltage, current and power.Circular Motion & Centripetal ForceSwing a ball on a string and drag it to change the radius and speed.Climate Chemistry: CO₂ & TemperatureChange CO₂ levels and see the greenhouse effect warm the planet.Collision Lab: 2D Momentum & Kinetic EnergyCrash balls of different masses on a table and track total momentum and kinetic energy for bouncy or sticky collisions.Collision Theory SimulatorWatch molecules collide and see why only fast, well-oriented collisions react.Collisions & Momentum LabCrash two carts together and compare momentum and kinetic energy before and after.Color Theory LabBuild colour harmonies on a wheel and check text contrast against WCAG.Color Vision: How We See ColourMix red, green and blue flashlights or choose one wavelength and see how your three cone types respond.Conservation of Angular Momentum: SpinningPull a spinning skater's arms in and watch her spin speed up exactly as L = Iω is conserved, or drop one spinning disk onto another and see them lock together.Continental Drift & Plate Motion SimulatorDrag two plates and set their velocities to build convergent, divergent or transform boundaries, then watch mountains, rifts and earthquakes appear in a live cross-section.Coulomb's Law: Force Between ChargesDrag two charges along a ruler, change their size and sign, and see the electric force between them.Curve Fitting: Best-Fit Line & RegressionDrag data points and watch the best-fit line, quadratic and cubic curves and R² update.DC Motor Simulator: Torque, Speed & Back-EMFSpin a permanent-magnet DC motor against a load, watch it settle onto its torque-speed curve, and see it stall if the load is too heavy.Density Lab: Mass, Volume & Identify theWeigh mystery blocks, measure their volume by water displacement and work out the material from the density.Derivative VisualizerDrag a point along a curve and see the tangent line and the derivative graph appear.Diffraction Grating & Spectrometer LabShine light through a diffraction grating and watch the bright orders land exactly where d sinθ = mλ predicts, then try to overlap two colors' orders.Diffusion & Osmosis SimulatorSee solute and water move across a membrane and find out why water follows the higher concentration.Digital Filter Designer: Low-Pass & High-PassDesign a real RC low-pass or high-pass filter, watch its Bode magnitude plot draw live, and see exactly how much a signal is attenuated at any frequency.Digital Logic Gate SimulatorBuild circuits from AND, OR, NOT, NAND, NOR, XOR and XNOR gates, wire toggleable inputs to outputs and watch every signal propagate live, with an auto-generated truth table, Boolean expression, Karnaugh map and a NAND/NOR-only challenge mode for whatever you build.Distillation Setup LabAssemble a full distillation apparatus, fix thermometer and cooling-water mistakes, heat carefully, and read the boiling-point plateau as you separate two liquids.DNA Replication & Protein Synthesis SimulatorStep through DNA replication, transcription and translation of a short gene using real base-pairing and a genetic code table, then introduce a mutation and classify its effect.DNA Replication GameDrag the matching bases onto the unzipped DNA strand to build the copy, or type your own sequence.Doppler Effect SimulatorMove a sound source and an observer and hear how the pitch changes with speed.Double Slit & DiffractionChange wavelength and slit spacing and see the interference pattern and its intensity graph.Earthquake & Seismic Wave LaboratoryTrigger a virtual earthquake, watch P, S and surface waves radiate outward, read live seismograph traces at three stations, and triangulate the epicenter from S−P intervals.Electric Field & Charges SimulatorDrag positive and negative charges around and watch the field lines and forces react.Electric Potential & Equipotential Lines LabDrag a test point around two charges and read its potential and field live, then find where moving along an equipotential line takes zero work.Electrical Power Transformer & TransmissionStep a generator's voltage up through an ideal transformer, send the power down a resistive transmission line, and watch the current, I²R line loss and transmission efficiency all update live against the same delivered power.Electrolysis of WaterSplit water into hydrogen and oxygen and watch the bubbles collect in a 2:1 ratio.Electroplating Cell & Faraday's LawPlate an object with copper, silver, nickel, zinc or gold and calculate the mass and thickness from the current.Emission Spectrum ViewerA virtual spectrometer: 20 gases, emission, absorption and hot-solid views, an adjustable slit, UV to infrared, a hydrogen energy-level diagram and a mystery-element challenge.Energy Forms and Changes: Heat TransferHeat or cool an iron block, a brick and water, put them together and watch thermal energy flow with a live energy chart.Energy Skate ParkDrag a skater around a track and watch kinetic, potential and thermal energy trade places.Enthalpy & Activation Energy DiagramDrag the reactant, peak and product levels of an energy profile and see ΔH, Ea and the effect of a catalyst.Enzyme Activity SimulatorChange substrate, temperature, pH and inhibitors and watch the reaction rate of an enzyme.Enzyme Kinetics LaboratoryChange substrate, enzyme, temperature, pH and inhibitors, and watch a live Michaelis-Menten curve - then switch to a Lineweaver-Burk plot to estimate Vmax and Km yourself.Exoplanet Detection Lab: Transit & RadialTune a planet's size, mass and orbit and see whether the transit dip or the radial-velocity wobble is strong enough to detect above real instrument noise.Exponential Growth & Decay ExplorerCompare multiplying and adding growth for bacteria, savings, radioactive decay and viral videos, with a log scale option.Faraday's Law & Generator LabMove a magnet through a coil to light a bulb, or spin the generator and watch the induced voltage.Flower Anatomy & Pollination SimulatorClick a flower's parts to learn stigma, style, ovary, anther, filament, petal and sepal, then choose a pollination method and watch a fruit develop.Fluid Pipe Network & Pump Sizing LabSize a pipe run and a centrifugal pump, watch water flow through the pipe live, and see exactly where the pump curve and system curve meet to set the real operating flow and head.Forces & Friction SimulatorPush a block and explore Newton's laws, static and kinetic friction.Forces and Motion: Newton's Second LawPush a cart with different forces and friction and see acceleration, speed and net force.Fossil Formation & Geological Time SimulatorBury an organism and control burial depth, oxygen exposure and time to see it fossilize through compaction and mineral replacement, then read the sediment layers using relative dating.Fourier: Making WavesDrag harmonic amplitudes and watch sine waves add up to square, sawtooth and triangle waves.Fraction Builder: Compare, Add & EquivalentBuild two fractions with bars, circles and a number line, compare them, find equivalent fractions and add them.Free Fall & Motion GraphsDrop or throw an object and watch position and velocity graphs build in real time.Galvanic CellBuild a battery from two metals and watch electrons flow, with the cell voltage.Gas Laws SimulatorChange temperature, volume and particles to see pressure follow PV = nRT.Gear Train & Mechanical Advantage DesignerBuild a real two-stage compound gear train, watch the gears mesh and turn, and read off the true speed and torque the math predicts.Gear Train SimulatorDrag gears together to mesh them, then see speed and torque change through the train.Geometric TransformationsDrag a shape to translate, rotate and scale it and see the transformation matrix.Geothermal Energy & Earth's Interior SimulatorDrill a virtual geothermal well into an Earth cross-section and compute real temperature-versus-depth, extracted thermal energy and electrical power output.Gravitational Field & Escape Velocity LabPick a world, launch a rocket straight up and see whether it falls back or truly escapes, with the real field strength and escape speed live.Gravity & Orbits SandboxDrag planets, set their velocity and watch gravity build orbits, slingshots and collisions.Gravity Force LabDrag two masses and change their size to see how the gravity force depends on mass and distance.Greenhouse Effect & Earth's Energy BalanceChange the sun, reflectivity and greenhouse gases and see the surface temperature of Earth, Venus, Mars or Snowball Earth.Groundwater & Aquifer SimulatorWatch the water table rise and fall with rainfall and pumping, place a well, and see a contamination plume spread toward it through a permeable aquifer.Gyroscopic Precession LabSpin a wheel fast, hang a weight off its axle, and watch the whole axle slowly sweep around instead of falling - real torque-induced precession.Heart Pump & Cardiac CycleFollow one heartbeat through the four chambers, valves, ECG trace and blood pressure.Heat Conduction Through a Wall: Fourier's LawChange a wall's thickness, area and material, or stack layers of brick and insulation in series, and watch the heat flow and temperature gradient update live using Fourier's law.Heat Exchanger Design LabSwitch between counter-flow and parallel-flow, size a real heat exchanger, and watch the hot and cold temperature profiles run the length of the unit while effectiveness-NTU and LMTD agree on the same heat duty.Heat Exchanger Simulator: Parallel-Flow vsRun a hot and a cold fluid stream through a simple exchanger in parallel-flow or counter-flow, set the inlet temperatures, flow rates and heat transfer area, and compare the outlet temperatures, LMTD and effectiveness live.Heating Curve ExperimentAdd heat to ice and watch temperature versus time, including the flat melting and boiling plateaus.Hooke's Law: Springs and ForcesPull a spring with your mouse and see the force grow in proportion, with a force-displacement graph.Hubble's Law & Redshift LabWatch a galaxy's spectral lines redshift with distance, plot a Hubble diagram, and measure the expansion rate of the universe for yourself.Human Digestion SimulatorBuild a meal, feed it through the digestive tract, and watch real enzymes break carbohydrates, protein and fat down while a graph tracks nutrient absorption over time.Human Musculoskeletal Movement SimulatorPick a joint, activate a muscle, and watch it flex the joint against a load - with live torque, mechanical advantage and a real load-versus-force experiment.HVAC & Heat Pump SimulatorSet a thermostat and watch a heat pump cycle move heat in or out of a house.Hydraulic Press & Pascal's PrinciplePush a small piston and lift a car with a big one, and see how force, area and distance trade off.Inclined Plane SimulatorDrag the block and tilt the ramp yourself, flick it, and watch forces, speed and energy update live.Integral & Area Under CurveDrag the limits, choose the number of rectangles and compare Riemann sums with the exact area.Ionic vs Covalent BondsChange electronegativity difference and watch bonds go from covalent to polar to ionic.Isotopes & Average Atomic Mass MixerMix isotopes of chlorine, copper, boron and more and see the weighted average atomic mass on the periodic table.John Travoltage: Static Electricity & SparksRub John's foot on the carpet, collect charge, and bring his finger close to the doorknob to make a spark.Kepler's Laws of Planetary MotionChange orbit size and shape, see equal-area sectors and check the period–distance law.Kinematics Graph MatcherDrag a runner so its position-time graph matches the target line, then get a score.Kirchhoff's Rules: Multi-Loop Circuit LabChange the EMFs and resistors in a real two-loop circuit and watch all three branch currents solve live from Kirchhoff's voltage and current laws.Ladybug Motion 2D: Velocity & AccelerationDrag a ladybug around, or let it move in a line, circle or ellipse, and see its velocity and acceleration arrows change live.Le Chatelier's PrincipleChange concentration, temperature and pressure on N₂ + 3H₂ ⇌ 2NH₃ and watch the equilibrium shift.LED Circuit Designer & Resistor CalculatorBuild LED circuits with a battery, resistor, LED, switch and meters, watch real current and brightness, break them on purpose, and use 11 resistor calculators.Lens & Mirror Ray DiagramDrag the object and the focal point and watch the principal rays form the image.Light Refraction SimulatorBend a light ray between air, water, glass and diamond and find the critical angle.Limiting Reagent & Stoichiometry CalculatorType any reaction, enter grams of each reactant and find the limiting reagent and yield.Linear Equation ExplorerChange slope and intercept or drag two points to see the line, its equation and intercepts.Logistic Growth & Carrying Capacity LabRun the real logistic growth equation, add a harvesting rate, and find the maximum sustainable yield or push a population to collapse.Lunar Lander: Land Softly Physics GameFire the engine and tilt the lander to touch down softly on the pad, on the Moon, Mars or Earth.Magnet & Compass: Magnetic Field LinesDrag a bar magnet and a compass to see the magnetic field direction, strength and field lines.Magnetic Field & Compass SimulatorDrag a bar magnet around a grid of compasses and watch the field lines turn.Magnets and ElectromagnetsPower a coil with a battery, add loops, flip the current and drag a compass to see the field.Masses and Springs: Bounce LabHang masses on two springs, compare stiffness, gravity and damping, and measure the bounce period.Material Fatigue & S-N Curve LabCycle a loaded part through repeated stress, watch the waveform run, and read off the S-N curve exactly how many cycles it should survive before it fails.Mineral Identification LaboratoryRun real mineral tests — streak, Mohs hardness, luster, cleavage, density by displacement, magnetism and acid reaction — to identify an unknown specimen.Molarity & Dilution SimulatorDissolve a solute, see the concentration, and work out how much water to add to dilute it.Molecule BuilderAdd atoms and see which real molecule you have built, with a 3D model and name.Molecule Polarity SimulatorChange atom electronegativity and see bond dipoles, the net dipole and molecule polarity.Molecule ShapesDrag bonds and lone pairs onto a central atom, rotate it in 3D, and explore real molecules.Molecules and Light: Greenhouse EffectShine microwave, infrared, visible or ultraviolet light on molecules and see which absorb it and what happens.Moon Phases SimulatorMove the Moon around its orbit and see what phase looks like from Earth.Mountain Building SimulatorCompress a crustal block with adjustable plate velocity, rock strength and erosion, and watch a mountain range grow in real time cross-section, surface and stress views.Moving Man: Position, Velocity & AccelerationDrag the person along the track and watch position, velocity and acceleration graphs build.Natural Selection SimulatorWatch fur colour evolve in a bunny population as predators hunt and the environment changes.Neuron & Action Potential SimulatorStimulate a neuron and watch it fire (or fail to fire) an action potential, with a live resting → threshold → depolarization → repolarization → hyperpolarization voltage graph.Neuron Firing SimulatorStimulate a neuron and watch the action potential travel along the axon.Normal Modes: Coupled OscillatorsDrag masses on springs, excite each normal mode and see how every motion is a mix of modes.Ocean Acidification LabRaise atmospheric CO₂ and watch ocean pH fall and carbonate ions disappear, using the real carbonic acid chemistry behind ocean acidification.Ocean Acidification SimulatorSee how dissolved CO₂ lowers ocean pH and threatens shell-forming animals.Ohm's Law SimulatorChange voltage and resistance and see the current, the V = I R equation letters and a bulb brightness change.Orbital HybridizationStep through promotion, hybridisation and bonding for nine molecules with a rotating 3D hybrid-orbital picture.Orbital Motion & Gravity SimulatorLaunch a planet around a star and see circular, elliptical and escape orbits.Organic Reaction Pathways GameDrag reagents onto compounds to convert ethane, ethene, ethanol, ethanoic acid and esters, and take route challenges.Ozone Layer & UV Radiation LabRun a simplified Chapman cycle: balance ozone production against natural and CFC-driven catalytic destruction, and watch surface UV respond.Paper Chromatography & Rf ValuesSeparate the dyes of an ink on paper, choose the solvent and measure the Rf value of each dye.Pendulum Lab SimulatorExplore period, gravity and energy with a swinging pendulum.Periodic Trends ExplorerColour the periodic table by radius, electronegativity or ionisation energy and see the trends.pH Scale SimulatorTest everyday liquids and see pH, hydrogen and hydroxide ions, and acid or base.Photoelectric Effect SimulatorShine light on a metal and see when electrons are emitted, and how fast.Photosynthesis & Limiting FactorsMove the lamp, change CO₂ and temperature and count the oxygen bubbles from a pond plant.Photosynthesis Simulator: Inside theZoom inside a chloroplast and control light, CO₂, temperature and water to see the light-dependent and light-independent reactions speed up, slow down or stall.Phototropism & Gravitropism LabRotate the pot and move the light, predict which way the shoot and root will grow, then run the simulation and check your prediction.PID Control System SimulatorTune a PID controller driving a simulated DC motor toward a target speed, watch the response live, and feel what each of P, I and D actually does.PID Controller Tuning LabTune proportional, integral and derivative gains on a real first-order plant, watch the closed-loop step response redraw with a sweeping time marker, and read off the true overshoot, settling time and steady-state error.Pipe Flow & Reynolds Number SimulatorPick a fluid and a pipe, set the flow rate, and watch whether it flows in smooth layers or chaotic turbulence.Plant Genetics & Mendelian InheritanceCross two parent plants for flower colour, seed shape or height, build the Punnett square, then breed real offspring and compare the ratio to Mendel's theory.Plant Hormone SimulatorDial up auxin, gibberellin, cytokinin, ethylene and ABA and watch a plant bend toward light, stretch taller, branch out, ripen fruit or drop its leaves.Plant Nutrient Deficiency LaboratoryDiagnose a mystery plant's hidden nutrient deficiency from real symptom patterns - which leaves are affected and how - then submit your answer.Plant Transpiration LaboratoryControl humidity, temperature, wind and stomatal aperture in a sealed chamber, zoom on the stomata, and measure the transpiration rate live.Plant Water Transport: Xylem SimulatorFollow water from root to leaf through the xylem, and see how transpiration, root pressure and vessel width set the water's speed and pressure.Plate Tectonics & EarthquakesWatch plates collide, spread apart and slide past each other to build volcanoes, ridges and earthquakes.Plinko Probability: Galton BoardDrop balls through pegs and watch the bell-shaped binomial distribution build, with the theory curve.Polarization of Light: Malus's Law LabTurn a polarizing filter and watch the transmitted light dim exactly as I = I0 cos²θ predicts, then bring light back through crossed filters with a third one.Precipitation Reactions LabMix real quantities of ionic solutions, watch a staged nucleation-and-settling animation, check Q against Ksp, then filter, weigh and calculate percent yield.Predator-Prey Population SimulatorWatch rabbit and fox populations rise and fall with the Lotka-Volterra model.Probability LabFlip coins and roll dice thousands of times and compare results with theory.Projectile Data Lab: Air Resistance & TargetFire golf balls, pumpkins and pianos with and without air resistance and collect a table of ranges.Projectile Motion SimulatorLaunch a projectile and watch its path, range and max height change live.Pulley System SimulatorPull the rope, see how more rope strands cut the force you need but lengthen the pull.Punnett Square CalculatorCross two parents and get genotype and phenotype ratios, for one trait or two.Quadratic Function ExplorerDrag a, b and c to see the parabola, roots, vertex and discriminant change.Quantum Coin TossToss a quantum coin, put it in superposition, measure it and see interference bring it back to heads.Quantum Measurement: Stern-Gerlach ExperimentSend spin particles through analyzers along Z and X and see how measurement changes the state.Quantum Wave InterferenceFire photons, electrons or neutrons one at a time and watch the wave pattern build dot by dot.Radioactive Decay & Half-Life SimulatorWatch hundreds of unstable atoms decay at random and compare the count with the half-life curve.RC Circuit & Capacitor SimulatorCharge and discharge a capacitor through a resistor and watch voltage and current change.Reaction Mechanism & Rate-Determining StepSee a two-step mechanism as an energy profile, drag the peaks and find the slowest step and rate law.Reaction Rate SimulatorChange temperature and concentration and see how fast a reaction goes.Redox TrackerAnalyse any redox reaction you type, see who is oxidised and reduced, then test yourself.Reflex Arc & Nervous System SimulatorTrigger a stimulus and watch it race through the reflex arc, then compare a fast one-synapse knee-jerk reflex with a slower multi-synapse withdrawal reflex.Reinforced Concrete Beam DesignerPick a beam's width, depth, concrete and steel strengths and rebar, and watch the moment capacity and the ductile/brittle reinforcement check update live.Resistance in a WireChange a wire's length, thickness and material and watch electrons collide and the resistance change.Resonance Lab: Driven OscillatorsShake five springs and masses at different frequencies and see the one whose natural frequency matches swing wildly.Resonance Structures & DelocalisationSee the resonance forms of ozone, nitrate, carbonate, nitrite and benzene and the averaged hybrid.Respiratory System & Lung VentilationChange breathing rate, tidal volume, airway resistance and lung compliance, and watch the lungs and alveoli move air and exchange gas in real time.Rock Cycle LaboratoryDrag a rock sample through weathering, compaction, heat and pressure and watch it transform between igneous, sedimentary and metamorphic rock.Rocket Thrust & Launch SimulatorSet fuel, engine efficiency and throttle, launch a rocket and see altitude and speed graphs.Rutherford Scattering: Discovering the NucleusFire alpha particles at gold atoms and compare the plum pudding and nuclear models.Sediment Transport & River Erosion LabAdjust slope, discharge, channel width and grain size and use the real Hjulström curve to predict whether a river erodes, transports or deposits sediment — then add a dam and watch downstream effects.Seed Germination SimulatorSet temperature, moisture, oxygen, light and planting depth, then watch a seed move through imbibition, radicle, root, shoot and first leaves.Shaft Torsion & Angle of Twist SimulatorApply a motor torque to a solid or hollow shaft and watch it visibly twist, with live shear stress, angle of twist, power transmitted and a pass/fail safety check.Sine & Cosine Wave Explorer: AmplitudeShape y = A sin(B(x - C)) + D by dragging handles on the graph and see each change in the equation.Solar & Lunar Eclipse Geometry SimulatorMove the Moon through its real tilted orbit and see exactly why eclipses need both the right phase AND the right node crossing.Solar Panel Angle & Power SimulatorTilt a solar panel, move the sun across the sky and add clouds to see the power through the day.Solar System Builder & Kepler's LawsDrag planets to new orbits, change the star's mass and check Kepler's third law.Solubility Curve ExplorerDrag a point on the solubility graph and see whether the solution is unsaturated, saturated or super-saturated.Sound Wave & Frequency SimulatorSee sound as moving air particles and an oscilloscope trace, change pitch, and hear beats form.Sound Waves: Two Speakers & InterferencePlay a note through two speakers, drag a listener around the room and find the loud and silent spots.Special Relativity: Time Dilation & LengthPush a spaceship toward the speed of light and watch its onboard clock run slow and its length shrink, exactly as γ predicts.Spring & Hooke's Law SimulatorPull a mass on a spring and explore oscillation, period, damping and energy.Spring-Damper Vibration & ResonancePull a mass on a spring and damper, compare damping types and shake the base to find resonance.Standing Waves on a String: Tension &Change a string's tension and mass density to change its wave speed, then tune the driving frequency until it locks onto a harmonic and clean standing-wave loops appear.States of Matter SimulatorHeat and cool particles to see solid, liquid and gas behaviour and phase changes.Stellar Life Cycle & H-R Diagram SimulatorBuild a star by mass and watch it evolve on the Hertzsprung-Russell diagram from the main sequence to its final fate.Stress-Strain / Tensile Test SimulatorPull a virtual specimen of steel, aluminum, copper or a brittle polymer and watch the live stress-strain curve trace through elastic, yielding, necking and fracture.Structural Column Buckling LabLoad a slender column and watch it sway toward Euler buckling as the applied load closes in on the critical load.Telescope & Microscope: Compound Optics LabSwitch between a telescope and a compound microscope, adjust the objective and eyepiece focal lengths, and watch the ray-traced image and total magnification update live.Thermal Expansion & Bimetal StripHeat or cool a metal bar and see how much it grows, then bend a bimetal strip.Thin-Film Interference LabChange a film's thickness and index and watch its reflected color shift, or find the exact quarter-wave thickness that cancels reflection for anti-reflective coatings.Torque & Rotational Inertia LabPush a wheel at different distances from its axle and see torque, moment of inertia, angular acceleration and angular momentum.Transformer Simulator: Turns Ratio, Losses &Build a step-up or step-down transformer, add winding resistance and core loss, and watch efficiency change as you load it.Truss Bridge Builder & Load TesterBuild a truss bridge from a template or from scratch, drive a truck over it and watch real tension, compression, stress, buckling and collapse from a stiffness-method solver.Under Pressure: Fluid Pressure & DepthDrag a pressure gauge into a tank and see how depth, density and gravity change pressure.Unit Circle & Trig ExplorerDrag around the unit circle and watch sine, cosine and tangent trace their waves.Vector Addition SimulatorDrag vectors on a grid, add them tip to tail and see the sum, its magnitude, angle and components.Vehicle Suspension & Shock 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STL and calculate snap-fit cantilever deflection and forceStepper Steps per mm, Belt Length & PulleySteps per mm for belts and lead screws, belt length and centre distance, speed and torqueSVG to STL ExtruderExtrude SVG shapes into a printable STL with holes, base plate and keyring option10-Minute Abs WorkoutCore, lower abs and standing abs workouts with a 3D coach12-Week Workout ProgramsThree full 12-week programs with automatic progression and deload weeks7-Day & 30-Day Fitness Challenge TrackerPush-up, squat, plank and more: daily targets, calendar and streak7-Minute WorkoutThe classic 12-exercise 7-minute workout with a 3D coach and voiceAMRAP & EMOM Workout TimerAMRAP, EMOM and For Time with voice, round counter and movementsArm Workout No EquipmentTriceps, biceps and shoulders at home with a 3D coachBack Workout at HomeBodyweight, dumbbell and band back workouts with a 3D coachBarbell Plate CalculatorWhich plates to load on each side, with a visual barBasketball Shot 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bar, any camera angleCamera Push-Up CounterYour camera counts every push-up and checks your form, from any angleCamera Sit-Up & Crunch CounterCounts sit-ups or crunches with your camera, from any angleCamera Squat CounterCounts your squats with the camera and checks depth, any angleCamera Workout ModeChain squats, push-ups, planks and more: the camera counts and the voice coachesChest & Shoulder Workout at HomePush-up variations and dumbbell presses with a 3D coachCricket Batting & Bowling AnalyzerBatting and bowling actions: arm speed, elbow, front knee, head stabilityCustom Workout Builder with Voice CoachChoose from 120+ exercises, set reps & sets, then follow the voiceCycling Calculators: Speed, Power, Gears & FTPSpeed/time/distance, watts needed, gear ratio and FTP zones in one pageDeload & Recovery Readiness AdvisorDaily readiness score: train hard, go light, rest or deloadDesk Exercise Reminder for Office WorkersMovement break reminders with 1-5 minute voice-guided desk 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Daily Diary150+ foods with calories, protein, carbs, fat and a daily food diaryGentle Rehab Routines: Back, Knee, Shoulder &Voice-guided gentle routines with 3D demos and clear safety notesGlute Bridge CounterCounts every glute bridge and prompts you to lift higherGlute Workout at HomeBridges, kicks and thrusts with a 3D demo and voice coachGolf Swing AnalyzerRecord or load a swing: tempo, rotation, head movement, compare two swingsGPS Run Tracker with MapTrack runs, walks and rides: distance, pace, splits, route map, GPX exportHeart Rate Zones CalculatorFind your 5 training zones and max heart rate by ageHip Hinge & Deadlift CounterCounts deadlifts, good mornings and hip hingesIdeal Weight CalculatorDevine, Robinson, Miller & Hamwi formulas plus a healthy BMI rangeInteractive Muscle MapTap a muscle to see what it does and the best exercises for itKick CounterCounts front, side and roundhouse kicks with your cameraKids PE Challenges & Class ScoreboardAnimal workouts, brain breaks and 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Music BPM CalculatorSteps per minute for your pace, and the pace for a song's BPMSenior Chair Exercises & Balance TestsChair workouts for older adults plus 30-second chair stand and balance testsShoulder Press CounterCounts every overhead press and checks you lock outSteps to Distance CalculatorConvert steps to km/miles, time and calories (and back)Strength Program CalculatorWeights for popular strength programs from your 1RMStrength Standards CalculatorHow strong are you? Bench, squat, deadlift levels by body weightStrength Workout for RunnersSingle-leg strength, glutes and core to run strongerStretch Routine Guide8 guided stretching routines with timers, sides and breathing cuesStretching Guides with Animations18 stretches with animated demos, steps, benefits and hold timesSweat Rate CalculatorHow much you sweat per hour and how much to drinkSwimming Calculators: Pace, Laps, Calories &Pace per 100 m, lap converter, calories burned and critical swim speedTennis Stroke AnalyzerForehand, backhand and serve: speed, rotation, knee bend, compare strokesText Reader with Highlighted WordsRead any text aloud and follow the highlighted wordTriceps Dip CounterCounts chair or bar dips from any angleVO2 Max CalculatorCooper, 1.5-mile, Rockport walk and resting heart rate methodsVoice CounterA voice counts out loud for you: up, down, by 2s, 5s or 10sWaist-to-Height & Waist-to-Hip RatioHealth-risk ratios from your waist, hip and heightWall Sit TimerTimes your wall sit and warns when you slide up or too lowWarm-Up Sets CalculatorRamp-up sets to your working weight, rounded to platesWeekly Workout PlannerChoose your days, goal and equipment, get a full week of workoutsWeight & Body Measurements TrackerTrack weight, waist, chest, hips, arms with charts and a goal lineWeight Loss Timeline CalculatorHow long to reach your goal weight, with a date and weekly projectionWorkout GeneratorPick muscles, equipment and minutes, get a full workout with animationsWorkout Log & History TrackerStreaks, a 20-week heat map and a log of every workoutYoga Flow BuilderBuild your own yoga flow from 50+ poses and let a voice guide youYoga Pose CheckerCamera checks your yoga pose joint by joint and tells you what to fixBrain Type Quiz — Fast Thinker, OverthinkerA short quiz that reveals your brain type with a shareable personality cardBroke Score — How Broke Are You Really?A funny but real 0-100% broke score from your income, spending and savingsCategory Rush GameName something in the category with a random letterClean Jokes TellerThousands of clean jokes with a punchline revealCompare Yourself to the WorldSee your estimated income and sleep percentile vs the world, based on cited averagesDigital Life Report — Brain Performance ScoreIn-page typing and reaction tests plus your habits, combined into one Brain Performance ScoreFive in a RowGomoku vs computer or a friend on one screenFocus Score Test — Real Timed Attention TestA real in-browser go/no-go attention test with a measured, timed scoreFuture Net Worth Simulator — Spend vs InvestCompare two real compound-interest projections: keep spending vs start investingGirls' Night Party GamesMost likely to... and Spill the Beans promptsGroup Story BuilderBuild a silly story one sentence at a timeHousie Tambola Number CallerNumber caller and ticket generator for HousieHow Well Do You Know Me?Friend and bride/groom quiz questionsLife in Numbers — How Much of Your LifeSee how many years you've spent asleep and on your phone, from your own numbersMafia Role DealerDeal secret Mafia roles and read the narrator scriptMancalaClassic Mancala vs computer or two playersMove-Out Readiness ScoreA real 50/30/20-style affordability score for moving out on your ownNever Have I Ever Questions1,200+ clean Never Have I Ever promptsOne Sentence About Your LifeA few quick picks generate one blunt, reflective sentence about where you're atOverthinking Score — Rumination Self-CheckA short self-report quiz based on real rumination-scale concepts, with a percentile scoreParty Bingo CardsBridal, baby shower, mehndi, birthday and girls' night bingoPass the Bomb GameHidden-timer party game: name one and pass it onPictionary Word GeneratorEasy, medium and hard drawing words with a timerRapid Fire Questions10 quick questions, 5 seconds eachRarity Score — How Rare Are You?An 8-question quiz that reveals how rare your everyday habits really areRiddles with AnswersBrain-teasing riddles, answer hidden until you tapRideshare Driver Profit Reality CheckReal effective hourly take-home after true vehicle costs, vs local minimum wageSilly Would You RatherAbsurd dilemmas with a group vote counterSleep Debt Calculator — Real Nights OwedReal arithmetic on how many full nights of sleep you're behind onSmarter Than Average QuizA 6-question logic trick-quiz with a percentile score vs a stated averageSticks GameTake 1 to 3 sticks; last stick losesSubscription Cost Reality CheckAdd your subscriptions and see the real annual total plus relatable comparisonsTeam Trivia BattleTeam quiz night with 4,600+ questionsText Personality AnalyzerPaste your own text for a heuristic style read — confident but impatient? Curious and detailed?Time Wasted on Phone — Lifetime CalculatorReal arithmetic on how many years of your life you'll spend on your phoneTongue Twister Challenge200+ tongue twisters to say three times fastTruth or Dare GeneratorClean truth and dare prompts, no repeatsTwo Truths and a LieTopic prompts and a score of who fooled the groupUndercover Word GameSpy word party game, pass one phone aroundWheel of NamesAdd names, spin the wheel and pick a fair random winner.Where Should You Live? Personality ArchetypeA fun quiz matching your preferences to a place archetype — not real relocation adviceWho Am I? Guessing GameHeads-up charades with a timer, 400 wordsWould You Rather Questions4,500 would-you-rather dilemmas3-Way Loan Comparison ToolCompare up to three real loan offers side by side — payment, total interest, and total cost — so you can see instantly which offer actually wins.401 CalculatorProject your 401(k) balance including employer match.529 College Savings Plan CalculatorProject tax-advantaged 529 plan growth toward a future college cost goal.Amortization CalculatorSee exactly how each payment splits between principal and interest over the life of your loan.Annuity CalculatorProject the future value of a stream of regular payments.Annuity Payout CalculatorConvert a lump sum into a guaranteed monthly payout.APR CalculatorSee the true annual cost of a loan once lender fees are blended in.Area ConverterFree area converter for square metres, square feet, acres and hectares.Auto Lease CalculatorEstimate your monthly lease payment using the money factor method.Auto Loan CalculatorCalculate your monthly car payment including trade-in and sales tax.Average Return CalculatorCalculate the compound annual growth rate between two values.Basic CalculatorA simple online calculator for everyday sums.Boat Loan CalculatorCalculate your monthly payment on a boat loan.Bond CalculatorEstimate a bond's price given face value, coupon and market yield.Budget CalculatorSplit your take-home income into needs, wants, and savings.Business Loan CalculatorCalculate monthly payment on a business loan including origination fee.Cash Back or Low Interest CalculatorCompare a manufacturer cash-back offer vs. a promotional low APR.CD CalculatorProject the maturity value of a Certificate of Deposit.College Cost CalculatorProject the future cost of college given inflation and years until enrollment.Commission CalculatorCalculate commission earned on a sale.Complex Number CalculatorCalculate with complex numbers online.Credit Card Payoff CalculatorSee how long a fixed monthly payment takes to clear a credit card balance.Currency CalculatorConvert between currencies using a manual exchange rate.Data Storage ConverterFree data storage converter for bytes, kilobytes, megabytes, gigabytes and terabytes.Debt Consolidation CalculatorCompare your current blended debt payments vs. one consolidation loan.Debt Snowball vs. Avalanche PlannerEnter every debt you owe and see the exact month-by-month order to pay them off two ways — Snowball (smallest balance first) and Avalanche (highest interest first) — with total interest for each strategy compared side by side.Debt-to-Income Ratio CalculatorLenders use DTI to judge how much of your income already goes to debt.Depreciation CalculatorCalculate straight-line depreciation for an asset.Down Payment CalculatorCalculate your down payment, loan amount, and whether you'll owe PMI.Emergency Fund CalculatorCalculate how much you need saved to cover 3–6 months of essential expenses.Energy ConverterFree energy converter for joules, calories, kilowatt-hours and BTU.Equation SolverSolve linear, quadratic and cubic equations and 2x2 systems.Estate Tax CalculatorEstimate federal estate tax owed above the exemption threshold.FHA Loan CalculatorEstimate payments including upfront and monthly mortgage insurance premium (MIP).Finance CalculatorCompound interest, loan and other finance sums in the calculator.Full Amortization Schedule GeneratorGenerate a complete month-by-month payment schedule for any loan — export it to CSV and see the balance payoff curve. This produces hundreds of exact calculated rows a chatbot cannot compute or hand you as a real file.Future Value CalculatorWhat will today's money be worth in the future?General Finance CalculatorTime-Value-of-Money: solve for Future Value given PV, PMT, rate and periods.HELOC CalculatorEstimate your available credit line and interest-only draw payment.Home Equity Loan CalculatorSee your available equity and estimated fixed loan payment.Hourly to Salary CalculatorConvert an hourly wage into annual, monthly and weekly salary equivalents.House Affordability CalculatorEstimate the maximum home price you can comfortably afford using the 28/36 rule.Inflation CalculatorSee what a past dollar amount is worth today (or in the future) after inflation.Interest Rate CalculatorSolve for the interest rate given a starting and ending value.Investment Interest CalculatorProject the growth of a lump-sum investment with compounding.Investment Portfolio RebalancerEnter your current holdings and target allocation — get the exact dollar amount to buy or sell in each asset class to rebalance, plus a live pie chart.IRR CalculatorCalculate the Internal Rate of Return for an initial investment and 3 years of cash flow.Job Offer Comparison ToolCompare two job offers beyond base salary — bonus, PTO value, benefits, and cost-of-living — to see which is actually worth more.Lease CalculatorEstimate a general equipment or asset lease payment.Length ConverterFree length converter for meters, feet, inches, kilometres and miles.Live Currency ConverterFetches live exchange rates from our currency API right now — not a guessed or outdated number a language model would make up.Marriage Tax CalculatorCompare combined tax filing jointly vs. as two single filers.Matrix CalculatorDeterminant, inverse and multiplication for matrices.Mortgage Extra-Payment "What-If" SimulatorDrag a live slider to see, in real time, exactly how many years and how much interest an extra monthly payment saves on your mortgage.Mortgage Payoff CalculatorSee how much time and interest an extra monthly payment can save.Mutual Fund CalculatorProject growth of a mutual fund investment including expense ratio drag.Net Worth TrackerTrack everything you own vs. everything you owe. Saves your entries in this browser so you can update it over time and watch the trend — something a stateless chatbot reply can never remember for you.Pay Stub GeneratorGenerate and print a real itemized pay stub with gross pay, tax withholding, deductions, and net pay — a formatted document, not just a spoken number.Payback Period CalculatorFind out how long it takes an investment to pay for itself.Payment CalculatorStandard loan payment calculator for any purpose.Pension CalculatorEstimate an annual defined-benefit pension payout.Personal Loan CalculatorCalculate your monthly payment on an unsecured personal loan.Present Value CalculatorWhat is a future sum of money worth today?Pressure ConverterFree pressure converter for pascal, bar, PSI, atmospheres and mmHg.Programmer CalculatorConvert and calculate in hex, binary, octal and decimal.Real Estate Appreciation CalculatorProject a property's future value and equity growth.Refinance CalculatorFind your breakeven point when refinancing to a new rate or term.Rent CalculatorEstimate a comfortable monthly rent budget using the classic 30% of gross income rule.Rental Property CalculatorEstimate cash flow, cap rate and cash-on-cash return for an investment property.Retirement CalculatorProject your retirement nest egg based on current savings and contributions.Retirement Withdrawal SimulatorSimulate spending down a retirement portfolio year by year with inflation-adjusted withdrawals and market growth — and see the exact year the money runs out, if ever.RMD CalculatorCalculate your Required Minimum Distribution using the IRS Uniform Lifetime Table.ROI CalculatorCalculate a simple return on investment percentage.Roth IRA CalculatorProject tax-free growth of a Roth IRA.Sales Tax CalculatorCalculate sales tax and total price, or back it out from a total.Savings CalculatorSee how a monthly savings habit grows over time.Self-Employment Tax CalculatorCalculate Social Security + Medicare tax owed on freelance/1099 net income.Simple Interest CalculatorInterest calculated only on the original principal — no compounding.Social Security CalculatorRough estimate of your monthly benefit based on average indexed earnings and claiming age.Speed ConverterFree speed converter for km/h, mph, knots and metres per second.Statistics Mode: Mean, Median, Std DevMean, median, standard deviation and more for a list of numbers.Student Loan / Repayment CalculatorCalculate your monthly student loan payment.Take-Home Paycheck CalculatorEstimate net pay per paycheck after federal tax and FICA.Temperature ConverterFree temperature converter for Celsius, Fahrenheit and Kelvin.Time ConverterFree time converter for seconds, minutes, hours, days, weeks and years.Traditional IRA CalculatorProject tax-deferred growth of a Traditional IRA.VA Mortgage CalculatorEstimate payments for a VA loan including the funding fee.Volume ConverterFree volume converter for litres, gallons, cups, millilitres and fluid ounces.Weight ConverterFree weight converter for kilograms, pounds, ounces, grams and stones.3D Geometry ViewerRotate seven 3D solids and calculate volume, surface area, faces, edges and vertices.3D Molecule ViewerRotate, zoom and switch between ball-and-stick and space-filling models of common molecules.4-Stroke Engine & Otto CycleWatch intake, compression, power and exhaust strokes with valves, spark and a pressure-volume diagram.AC Circuits: Resistor, Capacitor & InductorChange frequency and components and see voltage, current, phase and impedance in an AC circuit.Acid-Base LabAdd HCl or NaOH to water and watch a live pH meter and indicator colour.Acid-Base Titration SimulatorRun a full analytical titration bench: fill the burette, add titrant drop by drop or continuously, and watch the live pH meter and titration curve build as you go.Area Model Multiplication & the DistributiveSee multiplication as a rectangle, split it into four easier parts and watch the partial products add up.Atom BuilderBuild atoms from protons, neutrons and electrons and see the element, isotope and charge.Atomic Interactions: Lennard-Jones PotentialDrag two atoms and see the attractive and repulsive forces and the Lennard-Jones potential graph.Atomic Orbital VisualizerSee the shapes of s, p and d orbitals and rotate them in 3D.Balance Beam & TorqueDrag weights onto a seesaw and balance the torques on both sides.Balancing Act: Torque & SeesawBalance a plank with bricks, crates and people, learn torque, and work out a mystery mass.Balloons & Static ElectricityRub a balloon on a sweater and watch it stick to the wall, showing charge transfer and induced charge.Beam Bending & Stress SimulatorMove a load along a beam, see deflection, the bending moment diagram and whether it stays safe.Beer's Law Lab: Absorbance & ConcentrationShine light through a colored solution and see how absorbance depends on concentration, width and wavelength.Bending Light: Refraction, Reflection & PrismAim a laser at water, glass or diamond, see reflection and refraction with angles, or split white light in a prism.Bernoulli's Principle & Fluid FlowSqueeze a pipe and watch the fluid speed up while the pressure gauge drops.Blackbody Spectrum & Wien's LawChange temperature and watch the blackbody curve, peak wavelength and glow colour of a hot object.Blood Flow & Circulatory System SimulatorFollow blood from the heart through arteries, arterioles, capillaries and veins, and see how strongly flow depends on vessel radius.Bohr Model of HydrogenMake the electron jump between energy levels and see the photons absorbed and emitted.Buffer Solution SimulatorAdd acid and base to a buffer and to plain water side by side and watch which one resists pH change.Build a Nucleus: Protons, Neutrons & StabilityDrag protons and neutrons to build atoms from hydrogen to calcium and check isotopes and stability.Buoyancy & Density LabDrag objects into fluid and see when they float or sink, with the buoyant force.Calculus Grapher: Derivative & IntegralDraw a function and see its derivative, or draw the derivative and see the function.Calorimetry & Specific Heat LabDrop a hot metal into water, plot the temperatures and calculate the specific heat capacity.Capacitor Lab: BasicsChange plate area, separation and voltage to see capacitance, charge and stored energy.Car Transmission & Gear Ratio SimulatorShift through the gears of a gearbox and see the gear pair, engine rpm, wheel speed, torque and speedometer.Carbon Cycle Simulator: Reservoirs & FluxesSet emissions, deforestation and uptake rates and watch carbon flow between the atmosphere, ocean, land biosphere and fossil reserves in a real mass-balance model.Cardiac Cycle & Wiggers Diagram LabDrive the heart through atrial systole, ventricular systole and diastole, watch the valves open and close, and read a real Wiggers-style pressure graph.Catalyst & Activation EnergySee how a catalyst lowers the activation energy barrier and speeds a reaction.Cell Membrane & Osmosis SimulatorPlace a cell in a hypotonic, isotonic or hypertonic solution and watch water cross the membrane while a live graph tracks the cell's volume.Center of Mass & BalanceDrag weights on a beam and place the support so it balances at the centre of mass.Central Limit Theorem: Sampling DistributionDraw samples from any population and watch the sample means pile up into a bell curve.Charges and Fields: Electric Field & VoltagePlace positive and negative charges, drag them, and see electric field arrows and voltage colours with a live sensor.Chemical Equation BalancerPractise with 1,700+ real equations, or type your own and balance it with charges.Chemical Equilibrium SimulatorWatch the forward and reverse reactions balance and apply Le Chatelier's principle.Circuit Construction Kit: DC & AC Virtual LabBuild real circuits with batteries, bulbs, resistors, fuses, switches, wires, capacitors, inductors and household objects, then measure them with a voltmeter and an ammeter.Circuit LabWire two resistors in series or parallel and see voltage, current and power.Circular Motion & Centripetal ForceSwing a ball on a string and drag it to change the radius and speed.Climate Chemistry: CO₂ & TemperatureChange CO₂ levels and see the greenhouse effect warm the planet.Collision Lab: 2D Momentum & Kinetic EnergyCrash balls of different masses on a table and track total momentum and kinetic energy for bouncy or sticky collisions.Collision Theory SimulatorWatch molecules collide and see why only fast, well-oriented collisions react.Collisions & Momentum LabCrash two carts together and compare momentum and kinetic energy before and after.Color Theory LabBuild colour harmonies on a wheel and check text contrast against WCAG.Color Vision: How We See ColourMix red, green and blue flashlights or choose one wavelength and see how your three cone types respond.Conservation of Angular Momentum: SpinningPull a spinning skater's arms in and watch her spin speed up exactly as L = Iω is conserved, or drop one spinning disk onto another and see them lock together.Continental Drift & Plate Motion SimulatorDrag two plates and set their velocities to build convergent, divergent or transform boundaries, then watch mountains, rifts and earthquakes appear in a live cross-section.Coulomb's Law: Force Between ChargesDrag two charges along a ruler, change their size and sign, and see the electric force between them.Curve Fitting: Best-Fit Line & RegressionDrag data points and watch the best-fit line, quadratic and cubic curves and R² update.DC Motor Simulator: Torque, Speed & Back-EMFSpin a permanent-magnet DC motor against a load, watch it settle onto its torque-speed curve, and see it stall if the load is too heavy.Density Lab: Mass, Volume & Identify theWeigh mystery blocks, measure their volume by water displacement and work out the material from the density.Derivative VisualizerDrag a point along a curve and see the tangent line and the derivative graph appear.Diffraction Grating & Spectrometer LabShine light through a diffraction grating and watch the bright orders land exactly where d sinθ = mλ predicts, then try to overlap two colors' orders.Diffusion & Osmosis SimulatorSee solute and water move across a membrane and find out why water follows the higher concentration.Digital Filter Designer: Low-Pass & High-PassDesign a real RC low-pass or high-pass filter, watch its Bode magnitude plot draw live, and see exactly how much a signal is attenuated at any frequency.Digital Logic Gate SimulatorBuild circuits from AND, OR, NOT, NAND, NOR, XOR and XNOR gates, wire toggleable inputs to outputs and watch every signal propagate live, with an auto-generated truth table, Boolean expression, Karnaugh map and a NAND/NOR-only challenge mode for whatever you build.Distillation Setup LabAssemble a full distillation apparatus, fix thermometer and cooling-water mistakes, heat carefully, and read the boiling-point plateau as you separate two liquids.DNA Replication & Protein Synthesis SimulatorStep through DNA replication, transcription and translation of a short gene using real base-pairing and a genetic code table, then introduce a mutation and classify its effect.DNA Replication GameDrag the matching bases onto the unzipped DNA strand to build the copy, or type your own sequence.Doppler Effect SimulatorMove a sound source and an observer and hear how the pitch changes with speed.Double Slit & DiffractionChange wavelength and slit spacing and see the interference pattern and its intensity graph.Earthquake & Seismic Wave LaboratoryTrigger a virtual earthquake, watch P, S and surface waves radiate outward, read live seismograph traces at three stations, and triangulate the epicenter from S−P intervals.Electric Field & Charges SimulatorDrag positive and negative charges around and watch the field lines and forces react.Electric Potential & Equipotential Lines LabDrag a test point around two charges and read its potential and field live, then find where moving along an equipotential line takes zero work.Electrical Power Transformer & TransmissionStep a generator's voltage up through an ideal transformer, send the power down a resistive transmission line, and watch the current, I²R line loss and transmission efficiency all update live against the same delivered power.Electrolysis of WaterSplit water into hydrogen and oxygen and watch the bubbles collect in a 2:1 ratio.Electroplating Cell & Faraday's LawPlate an object with copper, silver, nickel, zinc or gold and calculate the mass and thickness from the current.Emission Spectrum ViewerA virtual spectrometer: 20 gases, emission, absorption and hot-solid views, an adjustable slit, UV to infrared, a hydrogen energy-level diagram and a mystery-element challenge.Energy Forms and Changes: Heat TransferHeat or cool an iron block, a brick and water, put them together and watch thermal energy flow with a live energy chart.Energy Skate ParkDrag a skater around a track and watch kinetic, potential and thermal energy trade places.Enthalpy & Activation Energy DiagramDrag the reactant, peak and product levels of an energy profile and see ΔH, Ea and the effect of a catalyst.Enzyme Activity SimulatorChange substrate, temperature, pH and inhibitors and watch the reaction rate of an enzyme.Enzyme Kinetics LaboratoryChange substrate, enzyme, temperature, pH and inhibitors, and watch a live Michaelis-Menten curve - then switch to a Lineweaver-Burk plot to estimate Vmax and Km yourself.Exoplanet Detection Lab: Transit & RadialTune a planet's size, mass and orbit and see whether the transit dip or the radial-velocity wobble is strong enough to detect above real instrument noise.Exponential Growth & Decay ExplorerCompare multiplying and adding growth for bacteria, savings, radioactive decay and viral videos, with a log scale option.Faraday's Law & Generator LabMove a magnet through a coil to light a bulb, or spin the generator and watch the induced voltage.Flower Anatomy & Pollination SimulatorClick a flower's parts to learn stigma, style, ovary, anther, filament, petal and sepal, then choose a pollination method and watch a fruit develop.Fluid Pipe Network & Pump Sizing LabSize a pipe run and a centrifugal pump, watch water flow through the pipe live, and see exactly where the pump curve and system curve meet to set the real operating flow and head.Forces & Friction SimulatorPush a block and explore Newton's laws, static and kinetic friction.Forces and Motion: Newton's Second LawPush a cart with different forces and friction and see acceleration, speed and net force.Fossil Formation & Geological Time SimulatorBury an organism and control burial depth, oxygen exposure and time to see it fossilize through compaction and mineral replacement, then read the sediment layers using relative dating.Fourier: Making WavesDrag harmonic amplitudes and watch sine waves add up to square, sawtooth and triangle waves.Fraction Builder: Compare, Add & EquivalentBuild two fractions with bars, circles and a number line, compare them, find equivalent fractions and add them.Free Fall & Motion GraphsDrop or throw an object and watch position and velocity graphs build in real time.Galvanic CellBuild a battery from two metals and watch electrons flow, with the cell voltage.Gas Laws SimulatorChange temperature, volume and particles to see pressure follow PV = nRT.Gear Train & Mechanical Advantage DesignerBuild a real two-stage compound gear train, watch the gears mesh and turn, and read off the true speed and torque the math predicts.Gear Train SimulatorDrag gears together to mesh them, then see speed and torque change through the train.Geometric TransformationsDrag a shape to translate, rotate and scale it and see the transformation matrix.Geothermal Energy & Earth's Interior SimulatorDrill a virtual geothermal well into an Earth cross-section and compute real temperature-versus-depth, extracted thermal energy and electrical power output.Gravitational Field & Escape Velocity LabPick a world, launch a rocket straight up and see whether it falls back or truly escapes, with the real field strength and escape speed live.Gravity & Orbits SandboxDrag planets, set their velocity and watch gravity build orbits, slingshots and collisions.Gravity Force LabDrag two masses and change their size to see how the gravity force depends on mass and distance.Greenhouse Effect & Earth's Energy BalanceChange the sun, reflectivity and greenhouse gases and see the surface temperature of Earth, Venus, Mars or Snowball Earth.Groundwater & Aquifer SimulatorWatch the water table rise and fall with rainfall and pumping, place a well, and see a contamination plume spread toward it through a permeable aquifer.Gyroscopic Precession LabSpin a wheel fast, hang a weight off its axle, and watch the whole axle slowly sweep around instead of falling - real torque-induced precession.Heart Pump & Cardiac CycleFollow one heartbeat through the four chambers, valves, ECG trace and blood pressure.Heat Conduction Through a Wall: Fourier's LawChange a wall's thickness, area and material, or stack layers of brick and insulation in series, and watch the heat flow and temperature gradient update live using Fourier's law.Heat Exchanger Design LabSwitch between counter-flow and parallel-flow, size a real heat exchanger, and watch the hot and cold temperature profiles run the length of the unit while effectiveness-NTU and LMTD agree on the same heat duty.Heat Exchanger Simulator: Parallel-Flow vsRun a hot and a cold fluid stream through a simple exchanger in parallel-flow or counter-flow, set the inlet temperatures, flow rates and heat transfer area, and compare the outlet temperatures, LMTD and effectiveness live.Heating Curve ExperimentAdd heat to ice and watch temperature versus time, including the flat melting and boiling plateaus.Hooke's Law: Springs and ForcesPull a spring with your mouse and see the force grow in proportion, with a force-displacement graph.Hubble's Law & Redshift LabWatch a galaxy's spectral lines redshift with distance, plot a Hubble diagram, and measure the expansion rate of the universe for yourself.Human Digestion SimulatorBuild a meal, feed it through the digestive tract, and watch real enzymes break carbohydrates, protein and fat down while a graph tracks nutrient absorption over time.Human Musculoskeletal Movement SimulatorPick a joint, activate a muscle, and watch it flex the joint against a load - with live torque, mechanical advantage and a real load-versus-force experiment.HVAC & Heat Pump SimulatorSet a thermostat and watch a heat pump cycle move heat in or out of a house.Hydraulic Press & Pascal's PrinciplePush a small piston and lift a car with a big one, and see how force, area and distance trade off.Inclined Plane SimulatorDrag the block and tilt the ramp yourself, flick it, and watch forces, speed and energy update live.Integral & Area Under CurveDrag the limits, choose the number of rectangles and compare Riemann sums with the exact area.Ionic vs Covalent BondsChange electronegativity difference and watch bonds go from covalent to polar to ionic.Isotopes & Average Atomic Mass MixerMix isotopes of chlorine, copper, boron and more and see the weighted average atomic mass on the periodic table.John Travoltage: Static Electricity & SparksRub John's foot on the carpet, collect charge, and bring his finger close to the doorknob to make a spark.Kepler's Laws of Planetary MotionChange orbit size and shape, see equal-area sectors and check the period–distance law.Kinematics Graph MatcherDrag a runner so its position-time graph matches the target line, then get a score.Kirchhoff's Rules: Multi-Loop Circuit LabChange the EMFs and resistors in a real two-loop circuit and watch all three branch currents solve live from Kirchhoff's voltage and current laws.Ladybug Motion 2D: Velocity & AccelerationDrag a ladybug around, or let it move in a line, circle or ellipse, and see its velocity and acceleration arrows change live.Le Chatelier's PrincipleChange concentration, temperature and pressure on N₂ + 3H₂ ⇌ 2NH₃ and watch the equilibrium shift.LED Circuit Designer & Resistor CalculatorBuild LED circuits with a battery, resistor, LED, switch and meters, watch real current and brightness, break them on purpose, and use 11 resistor calculators.Lens & Mirror Ray DiagramDrag the object and the focal point and watch the principal rays form the image.Light Refraction SimulatorBend a light ray between air, water, glass and diamond and find the critical angle.Limiting Reagent & Stoichiometry CalculatorType any reaction, enter grams of each reactant and find the limiting reagent and yield.Linear Equation ExplorerChange slope and intercept or drag two points to see the line, its equation and intercepts.Logistic Growth & Carrying Capacity LabRun the real logistic growth equation, add a harvesting rate, and find the maximum sustainable yield or push a population to collapse.Lunar Lander: Land Softly Physics GameFire the engine and tilt the lander to touch down softly on the pad, on the Moon, Mars or Earth.Magnet & Compass: Magnetic Field LinesDrag a bar magnet and a compass to see the magnetic field direction, strength and field lines.Magnetic Field & Compass SimulatorDrag a bar magnet around a grid of compasses and watch the field lines turn.Magnets and ElectromagnetsPower a coil with a battery, add loops, flip the current and drag a compass to see the field.Masses and Springs: Bounce LabHang masses on two springs, compare stiffness, gravity and damping, and measure the bounce period.Material Fatigue & S-N Curve LabCycle a loaded part through repeated stress, watch the waveform run, and read off the S-N curve exactly how many cycles it should survive before it fails.Mineral Identification LaboratoryRun real mineral tests — streak, Mohs hardness, luster, cleavage, density by displacement, magnetism and acid reaction — to identify an unknown specimen.Molarity & Dilution SimulatorDissolve a solute, see the concentration, and work out how much water to add to dilute it.Molecule BuilderAdd atoms and see which real molecule you have built, with a 3D model and name.Molecule Polarity SimulatorChange atom electronegativity and see bond dipoles, the net dipole and molecule polarity.Molecule ShapesDrag bonds and lone pairs onto a central atom, rotate it in 3D, and explore real molecules.Molecules and Light: Greenhouse EffectShine microwave, infrared, visible or ultraviolet light on molecules and see which absorb it and what happens.Moon Phases SimulatorMove the Moon around its orbit and see what phase looks like from Earth.Mountain Building SimulatorCompress a crustal block with adjustable plate velocity, rock strength and erosion, and watch a mountain range grow in real time cross-section, surface and stress views.Moving Man: Position, Velocity & AccelerationDrag the person along the track and watch position, velocity and acceleration graphs build.Natural Selection SimulatorWatch fur colour evolve in a bunny population as predators hunt and the environment changes.Neuron & Action Potential SimulatorStimulate a neuron and watch it fire (or fail to fire) an action potential, with a live resting → threshold → depolarization → repolarization → hyperpolarization voltage graph.Neuron Firing SimulatorStimulate a neuron and watch the action potential travel along the axon.Normal Modes: Coupled OscillatorsDrag masses on springs, excite each normal mode and see how every motion is a mix of modes.Ocean Acidification LabRaise atmospheric CO₂ and watch ocean pH fall and carbonate ions disappear, using the real carbonic acid chemistry behind ocean acidification.Ocean Acidification SimulatorSee how dissolved CO₂ lowers ocean pH and threatens shell-forming animals.Ohm's Law SimulatorChange voltage and resistance and see the current, the V = I R equation letters and a bulb brightness change.Orbital HybridizationStep through promotion, hybridisation and bonding for nine molecules with a rotating 3D hybrid-orbital picture.Orbital Motion & Gravity SimulatorLaunch a planet around a star and see circular, elliptical and escape orbits.Organic Reaction Pathways GameDrag reagents onto compounds to convert ethane, ethene, ethanol, ethanoic acid and esters, and take route challenges.Ozone Layer & UV Radiation LabRun a simplified Chapman cycle: balance ozone production against natural and CFC-driven catalytic destruction, and watch surface UV respond.Paper Chromatography & Rf ValuesSeparate the dyes of an ink on paper, choose the solvent and measure the Rf value of each dye.Pendulum Lab SimulatorExplore period, gravity and energy with a swinging pendulum.Periodic Trends ExplorerColour the periodic table by radius, electronegativity or ionisation energy and see the trends.pH Scale SimulatorTest everyday liquids and see pH, hydrogen and hydroxide ions, and acid or base.Photoelectric Effect SimulatorShine light on a metal and see when electrons are emitted, and how fast.Photosynthesis & Limiting FactorsMove the lamp, change CO₂ and temperature and count the oxygen bubbles from a pond plant.Photosynthesis Simulator: Inside theZoom inside a chloroplast and control light, CO₂, temperature and water to see the light-dependent and light-independent reactions speed up, slow down or stall.Phototropism & Gravitropism LabRotate the pot and move the light, predict which way the shoot and root will grow, then run the simulation and check your prediction.PID Control System SimulatorTune a PID controller driving a simulated DC motor toward a target speed, watch the response live, and feel what each of P, I and D actually does.PID Controller Tuning LabTune proportional, integral and derivative gains on a real first-order plant, watch the closed-loop step response redraw with a sweeping time marker, and read off the true overshoot, settling time and steady-state error.Pipe Flow & Reynolds Number SimulatorPick a fluid and a pipe, set the flow rate, and watch whether it flows in smooth layers or chaotic turbulence.Plant Genetics & Mendelian InheritanceCross two parent plants for flower colour, seed shape or height, build the Punnett square, then breed real offspring and compare the ratio to Mendel's theory.Plant Hormone SimulatorDial up auxin, gibberellin, cytokinin, ethylene and ABA and watch a plant bend toward light, stretch taller, branch out, ripen fruit or drop its leaves.Plant Nutrient Deficiency LaboratoryDiagnose a mystery plant's hidden nutrient deficiency from real symptom patterns - which leaves are affected and how - then submit your answer.Plant Transpiration LaboratoryControl humidity, temperature, wind and stomatal aperture in a sealed chamber, zoom on the stomata, and measure the transpiration rate live.Plant Water Transport: Xylem SimulatorFollow water from root to leaf through the xylem, and see how transpiration, root pressure and vessel width set the water's speed and pressure.Plate Tectonics & EarthquakesWatch plates collide, spread apart and slide past each other to build volcanoes, ridges and earthquakes.Plinko Probability: Galton BoardDrop balls through pegs and watch the bell-shaped binomial distribution build, with the theory curve.Polarization of Light: Malus's Law LabTurn a polarizing filter and watch the transmitted light dim exactly as I = I0 cos²θ predicts, then bring light back through crossed filters with a third one.Precipitation Reactions LabMix real quantities of ionic solutions, watch a staged nucleation-and-settling animation, check Q against Ksp, then filter, weigh and calculate percent yield.Predator-Prey Population SimulatorWatch rabbit and fox populations rise and fall with the Lotka-Volterra model.Probability LabFlip coins and roll dice thousands of times and compare results with theory.Projectile Data Lab: Air Resistance & TargetFire golf balls, pumpkins and pianos with and without air resistance and collect a table of ranges.Projectile Motion SimulatorLaunch a projectile and watch its path, range and max height change live.Pulley System SimulatorPull the rope, see how more rope strands cut the force you need but lengthen the pull.Punnett Square CalculatorCross two parents and get genotype and phenotype ratios, for one trait or two.Quadratic Function ExplorerDrag a, b and c to see the parabola, roots, vertex and discriminant change.Quantum Coin TossToss a quantum coin, put it in superposition, measure it and see interference bring it back to heads.Quantum Measurement: Stern-Gerlach ExperimentSend spin particles through analyzers along Z and X and see how measurement changes the state.Quantum Wave InterferenceFire photons, electrons or neutrons one at a time and watch the wave pattern build dot by dot.Radioactive Decay & Half-Life SimulatorWatch hundreds of unstable atoms decay at random and compare the count with the half-life curve.RC Circuit & Capacitor SimulatorCharge and discharge a capacitor through a resistor and watch voltage and current change.Reaction Mechanism & Rate-Determining StepSee a two-step mechanism as an energy profile, drag the peaks and find the slowest step and rate law.Reaction Rate SimulatorChange temperature and concentration and see how fast a reaction goes.Redox TrackerAnalyse any redox reaction you type, see who is oxidised and reduced, then test yourself.Reflex Arc & Nervous System SimulatorTrigger a stimulus and watch it race through the reflex arc, then compare a fast one-synapse knee-jerk reflex with a slower multi-synapse withdrawal reflex.Reinforced Concrete Beam DesignerPick a beam's width, depth, concrete and steel strengths and rebar, and watch the moment capacity and the ductile/brittle reinforcement check update live.Resistance in a WireChange a wire's length, thickness and material and watch electrons collide and the resistance change.Resonance Lab: Driven OscillatorsShake five springs and masses at different frequencies and see the one whose natural frequency matches swing wildly.Resonance Structures & DelocalisationSee the resonance forms of ozone, nitrate, carbonate, nitrite and benzene and the averaged hybrid.Respiratory System & Lung VentilationChange breathing rate, tidal volume, airway resistance and lung compliance, and watch the lungs and alveoli move air and exchange gas in real time.Rock Cycle LaboratoryDrag a rock sample through weathering, compaction, heat and pressure and watch it transform between igneous, sedimentary and metamorphic rock.Rocket Thrust & Launch SimulatorSet fuel, engine efficiency and throttle, launch a rocket and see altitude and speed graphs.Rutherford Scattering: Discovering the NucleusFire alpha particles at gold atoms and compare the plum pudding and nuclear models.Sediment Transport & River Erosion LabAdjust slope, discharge, channel width and grain size and use the real Hjulström curve to predict whether a river erodes, transports or deposits sediment — then add a dam and watch downstream effects.Seed Germination SimulatorSet temperature, moisture, oxygen, light and planting depth, then watch a seed move through imbibition, radicle, root, shoot and first leaves.Shaft Torsion & Angle of Twist SimulatorApply a motor torque to a solid or hollow shaft and watch it visibly twist, with live shear stress, angle of twist, power transmitted and a pass/fail safety check.Sine & Cosine Wave Explorer: AmplitudeShape y = A sin(B(x - C)) + D by dragging handles on the graph and see each change in the equation.Solar & Lunar Eclipse Geometry SimulatorMove the Moon through its real tilted orbit and see exactly why eclipses need both the right phase AND the right node crossing.Solar Panel Angle & Power SimulatorTilt a solar panel, move the sun across the sky and add clouds to see the power through the day.Solar System Builder & Kepler's LawsDrag planets to new orbits, change the star's mass and check Kepler's third law.Solubility Curve ExplorerDrag a point on the solubility graph and see whether the solution is unsaturated, saturated or super-saturated.Sound Wave & Frequency SimulatorSee sound as moving air particles and an oscilloscope trace, change pitch, and hear beats form.Sound Waves: Two Speakers & InterferencePlay a note through two speakers, drag a listener around the room and find the loud and silent spots.Special Relativity: Time Dilation & LengthPush a spaceship toward the speed of light and watch its onboard clock run slow and its length shrink, exactly as γ predicts.Spring & Hooke's Law SimulatorPull a mass on a spring and explore oscillation, period, damping and energy.Spring-Damper Vibration & ResonancePull a mass on a spring and damper, compare damping types and shake the base to find resonance.Standing Waves on a String: Tension &Change a string's tension and mass density to change its wave speed, then tune the driving frequency until it locks onto a harmonic and clean standing-wave loops appear.States of Matter SimulatorHeat and cool particles to see solid, liquid and gas behaviour and phase changes.Stellar Life Cycle & H-R Diagram SimulatorBuild a star by mass and watch it evolve on the Hertzsprung-Russell diagram from the main sequence to its final fate.Stress-Strain / Tensile Test SimulatorPull a virtual specimen of steel, aluminum, copper or a brittle polymer and watch the live stress-strain curve trace through elastic, yielding, necking and fracture.Structural Column Buckling LabLoad a slender column and watch it sway toward Euler buckling as the applied load closes in on the critical load.Telescope & Microscope: Compound Optics LabSwitch between a telescope and a compound microscope, adjust the objective and eyepiece focal lengths, and watch the ray-traced image and total magnification update live.Thermal Expansion & Bimetal StripHeat or cool a metal bar and see how much it grows, then bend a bimetal strip.Thin-Film Interference LabChange a film's thickness and index and watch its reflected color shift, or find the exact quarter-wave thickness that cancels reflection for anti-reflective coatings.Torque & Rotational Inertia LabPush a wheel at different distances from its axle and see torque, moment of inertia, angular acceleration and angular momentum.Transformer Simulator: Turns Ratio, Losses &Build a step-up or step-down transformer, add winding resistance and core loss, and watch efficiency change as you load it.Truss Bridge Builder & Load TesterBuild a truss bridge from a template or from scratch, drive a truck over it and watch real tension, compression, stress, buckling and collapse from a stiffness-method solver.Under Pressure: Fluid Pressure & DepthDrag a pressure gauge into a tank and see how depth, density and gravity change pressure.Unit Circle & Trig ExplorerDrag around the unit circle and watch sine, cosine and tangent trace their waves.Vector Addition SimulatorDrag vectors on a grid, add them tip to tail and see the sum, its magnitude, angle and components.Vehicle Suspension & Shock 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