How it works
Click the big pad to start. It turns red — wait for it — and flips green at a random moment between 1 and 3.5 seconds. The instant it's green, click. Your time is measured in milliseconds, and your best is saved in your browser.
Reading your score
- Under 200 ms: exceptional — pro-esports territory.
- 200–250 ms: better than average; sharp day.
- 250–320 ms: the broad human average for visual reactions.
- 320 ms+: normal for a cold start, late hours, or a trackpad — try a mouse and a second attempt.
Factors that move the number
Reaction time improves with a mouse (vs trackpad), worsens with age gradually after the mid-20s, degrades measurably when tired, and benefits enormously from the second and third attempts as your brain stops "deciding" and starts anticipating the pattern. The test measures simple visual reaction — the fastest reflex pathway humans have.