Explore the Digital Logic Gate Simulator
Build circuits from AND, OR, NOT, NAND, NOR, XOR and XNOR gates, wire toggleable inputs to outputs and watch every signal propagate live.
- Free to use
- No signup
- Nothing to install
- Runs in your browser
Illustration. Open the tool for the real thing.
See it in action
The Digital Logic Gate Simulator with sample data entered and the result showing.
What is the Digital Logic Gate Simulator?
Build 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. It runs in your browser, so a change to a setting or a drag on an object shows up at once.
Every processor, memory chip and embedded controller is built from millions of gates like these; digital electronics engineers use exactly this kind of gate-level design, truth tables and adder circuits to build calculators, CPUs, traffic light controllers and the arithmetic units inside every computer and smartphone.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
Every logic gate is just a rule for turning one or two 0/1 inputs into a single 0/1 output, and those simple rules are the building blocks of every digital computer.
AND is 1 only when both inputs are 1; OR is 1 when either input is 1; NOT simply flips its input.
NAND and NOR are AND and OR with the output inverted, and either one by itself is a universal gate: any Boolean circuit, including AND, OR and NOT, can be rebuilt using only NAND gates (or only NOR gates).
Load the Half Adder preset, then flip A and B and check the Sum and Carry against the live truth table and the Boolean expression shown above it.
Load the Full Adder preset and verify that A=1, B=1, Cin=1 gives Sum=1 and Cout=1, the same as 1+1+1=11 in binary.
Load the 2-to-1 Multiplexer preset, flip the select line S, and see how it switches which of I0 or I1 reaches the output Y.
Used for
Pick one to see how it fits.
Engineering learners
Engineering and technology students, makers, robotics clubs and teachers of design and technology.
Try it freeTeachers
For teachers: project the Digital Logic Gate Simulator on the board, let students predict the result, then run it together and test this: Load the Full Adder preset and verify that A=1, B=1, Cin=1 gives Sum=1 and Cout=1, the same as 1+1+1=11 in binary. For students: change one thing at a time and write down what changes.
Try it freeHow it compares
A plain look at this tool next to the usual alternative.
| This simulation | Textbook diagram | |
|---|---|---|
| Interactive | Drag, tap and change settings | Fixed picture |
| Install | Nothing to install | Not needed |
| Cost | Free to use | Depends on the book |
Questions people ask
What is the difference between AND, OR and XOR?
AND needs both inputs to be 1 to give a 1. OR needs at least one input to be 1. XOR (exclusive OR) needs the two inputs to be different from each other, so 1-0 or 0-1 gives 1, but 0-0 and 1-1 both give 0.
Why are NAND and NOR called universal gates?
Because you can wire NAND gates together (or NOR gates together) to reproduce the behaviour of AND, OR and NOT, so a whole computer chip can be manufactured from just one repeated type of gate, which is cheaper and simpler to fabricate.
How does the Half Adder become a Full Adder?
A Half Adder only adds two bits and produces a Sum and a Carry. A Full Adder adds a third input, the carry-in from a previous column, so it can be chained with other Full Adders to add numbers with many bits, one column at a time, exactly like adding by hand on paper.
What is the NAND-only or NOR-only challenge?
It hides every gate button except NAND (or except NOR) in the palette and challenges you to rebuild AND, OR, NOT and XOR using only that one gate. Since NAND (and separately NOR) is functionally complete, it is always possible, and the simulator tells you when your circuit's truth table matches a known gate.
Is the Digital Logic Gate Simulator free to use?
Yes. The Digital Logic Gate Simulator is free, needs no signup or download and runs in your web browser. It is part of the Engineering group of AZRS simulations.
More free tools
Related to the Digital Logic Gate Simulator.
Try the Digital Logic Gate Simulator now
Build circuits from AND, OR, NOT, NAND, NOR, XOR and XNOR gates, wire toggleable inputs. Free to use.
Try it free