What this test measures
Reaction time measures how fast you respond to a visual stimulus — the rawest index of nervous-system speed. The screen waits a random interval, then turns green; you click the instant it does. Your score is the average of five trials in milliseconds, and lower is better.
How to play
Wait for the red screen to turn green, then click (or tap) as fast as you can. Click too early and the trial resets. Five trials are averaged, and your fastest is shown too.
How to improve
- React to the colour change — don't try to predict the timing.
- Use a wired mouse and a high-refresh display; wireless and laggy screens add milliseconds.
- Compare your median across runs; a single lucky trial isn't your true speed.
Frequently asked questions
What is a good reaction time? Most people score 200–300 ms; elite reactions dip under 200 ms. Online scores run a little higher than lab values due to display and input lag.
Why is lower better? It is a speed measure — fewer milliseconds between the cue and your response is faster.
Is it free? Yes — free in the browser; scores save locally and sync after sign-in.
Related Reaction & Speed tests
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