Run your Arduino sketch online — no download
A free Arduino simulator that runs right in your browser. No install, no sign-up, no hardware — write a sketch, press Run, and watch simplified virtual LEDs, a buzzer, a servo, and the Serial Monitor. It is a learning model, not proof that real wiring is correct or safe.
Try this: Pin 13 turns on and off once a second. Watch LED 13 in the board panel. Or grab a ready-made sketch from the Arduino code library.
How to use the online Arduino simulator
- 1. Pick an example above, or paste your own sketch into the editor.
- 2. Press Run. The simulator interprets supported code as a simplified model of a real board.
- 3. Watch the virtual LEDs, buzzer and servo, and read Serial.println output in the Serial Monitor.
- 4. Drag the light-sensor slider or hold the button to feed the sketch new input.
- 5. Change a number and run it again. Before building it, ask a trusted adult to check the real wiring and power.
What you can simulate
The simulator supports digital output, analog input, delays, variables, loops, arrays, your own functions and the Servo library — enough for blink sketches, traffic lights, night lights, reaction games and sensor experiments. When your sketch works here, build it for real with a step-by-step project, learn the theory in the lessons, or test yourself with a challenge.