Reaction Time Test

Click to start, wait for the screen to turn green, then click as fast as you can. Your reaction is measured in milliseconds using a high-resolution timer. Click too early and it counts as a miss — no cheating the wait.

Most people land between 200 and 300 ms. Take several goes and watch the number settle; your best time is stored in your browser so you can beat it later.

How it works: everything runs in your browser — timing uses a high-resolution clock (performance.now()) and your best score is saved on this device only. Nothing is uploaded, and there's nothing to install.