How quickly can you react to a color change? Wait for the signal and test your reflexes across five rounds. See your average reaction time and try to beat your personal best.
Start a round and wait until the panel turns green. Click, tap, or press Space when you see the signal. Clicking early means you will need to try that round again. Your best five-round average is saved only in this browser.
Keyboard: press Space or Enter to start and react. Keep this tab visible while playing.