What is a reaction-time test?
This page measures the delay between a visual cue (green) and your click, in milliseconds. It’s a casual check—not a medical or professional timing instrument—and results vary by device and browser.
How to play
Press Start. The panel stays red for a random interval, then turns green. Click immediately when it turns green. While it’s red, the button stays enabled—clicking early counts as a foul. Your fastest time can be saved locally as a personal best.
Notes
Use results for fun and self-comparison only. Display and input hardware affect the number you see.