What's a 'good' reaction time?

200–270 ms is good for a healthy adult on a fresh page. Under 200 ms is exceptional. Over 350 ms can come from fatigue, OS input lag, or a high-refresh-rate browser tab being throttled in the background.

Does the screen refresh rate matter?

Yes, a little. A 60 Hz monitor can add up to 16 ms of latency between the color change and your eyes seeing it; a 120 Hz monitor shaves that in half. The test still measures clicks accurately to the millisecond.

Reaction Time Tester

Random

A classic visual reaction time test using `performance.now()` for sub-millisecond timing. The panel turns red while waiting (random 1.5–5 second delay so you can't anticipate), then green when it's go-time. Click too early during red and you reset; click during green and the elapsed milliseconds become your score. Human reaction time to a visual cue averages around 250 ms; under 200 ms is exceptional, anything over 350 ms suggests fatigue, distraction, or input lag.

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How to use

Click the panel to start. It turns red while it randomizes a wait.
When it flashes green, click as fast as you can — your time appears in ms.
Click again to retry. After several attempts the stat row shows your average, best, and worst.

Frequently asked questions

What's a 'good' reaction time?: 200–270 ms is good for a healthy adult on a fresh page. Under 200 ms is exceptional. Over 350 ms can come from fatigue, OS input lag, or a high-refresh-rate browser tab being throttled in the background.
Does the screen refresh rate matter?: Yes, a little. A 60 Hz monitor can add up to 16 ms of latency between the color change and your eyes seeing it; a 120 Hz monitor shaves that in half. The test still measures clicks accurately to the millisecond.