The free Compound Interest Calculator
Calculate how a lump sum or a regularly contributed savings amount grows with compound interest over time. Enter your principal, interest rate, compounding frequency and time period to see
- Free to use
- No signup
- Nothing to install
- Works in any modern browser
Your input
The actionA real example, step by step
Real data entered into the Compound Interest Calculator, one screenshot per step. Nothing is mocked up.
Open the tool
The Compound Interest Calculator opens ready to use, nothing to install or sign up for.
Enter your data
Real input used here: Principal Amount (Starting Investment) 10000; Annual Interest Rate (%) 5; Time Period (Years) 10.
Press Calculate Returns
The Compound Interest Calculator shows the result straight away, below the same form.
What is the Compound Interest Calculator?
Calculate how a lump sum or a regularly contributed savings amount grows with compound interest over time. Enter your principal, interest rate, compounding frequency and time period to see your final balance, total interest earned, and a breakdown of growth over time.
Compounding frequency matters: interest compounded monthly grows slightly faster than the same annual rate compounded yearly, because interest starts earning its own interest sooner. This calculator lets you compare frequencies directly.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
Compare annual, monthly, and daily compounding on the same principal and rate.
Model regular deposits on top of a starting balance.
See exactly how much of your final balance is interest earned.
No signup, results update as you change any input.
AZRS tools are free to open and use.
It opens in your browser, so there is nothing to download.
Used for
Pick one to see how it fits.
Students learning finance
Visualize the difference between simple and compound interest concretely.
Try it freeAnyone comparing accounts
Compare two accounts with different rates and compounding frequencies fairly.
Try it freeHow it compares
A plain look at this tool next to the usual alternative.
| This calculator | Desktop software | |
|---|---|---|
| Install | Nothing to install | Usually an app or program to install |
| Account | No signup | Depends on the product |
| Cost | Free to use | Free or paid, depends on the product |
Questions people ask
What is compound interest?
Interest calculated on both the original principal and any interest already earned, so the balance grows faster over time than with simple interest.
Does compounding frequency really matter?
Yes — more frequent compounding (daily vs. monthly vs. annually) produces a slightly higher final balance at the same stated annual rate.
What's the Rule of 72?
A quick estimate for how long it takes an investment to double: divide 72 by the annual interest rate. At 6%, that's about 12 years.
Is this compound interest calculator free?
Yes, free with no signup.
Can I add regular contributions?
Yes, enter an optional recurring deposit amount and frequency to see its effect on the final balance.
More free tools
Related to the Compound Interest Calculator.
Try the Compound Interest Calculator now
Calculate how a lump sum or a regularly contributed savings amount grows with compound. Free to use.
Try it free