Reaction Time Test
Click as soon as the box turns green. Five rounds, your average and best time at the end.
Click to start
You'll get 5 rounds. Wait for green, then click as fast as you can.
About this reaction time test
The box starts red. After a random pause — long enough that you can't reliably predict it — it turns green, and the clock is running from that exact instant until you click. Five rounds are averaged together, since any single click has enough natural variance that one result alone doesn't mean much.
Click too early, while the box is still red, and it's a false start rather than an impressively fast reaction — no time is recorded, and that round simply restarts with a new random delay. This matters for the test to mean anything: without it, guessing when the colour is "about due" and clicking early would look identical to genuinely fast reflexes.
Timing uses your browser's high-resolution clock, the same kind used for animation and performance measurement, rather than the ordinary system clock — appropriate given a typical human reaction sits somewhere around 200 to 300 milliseconds, and the measurement needs enough precision that it isn't the bottleneck.
Your best average across a completed set of five rounds is saved locally on your device, not your single fastest click, since a lucky one-off click is a much less stable thing to chase than a genuine average across several attempts.
Frequently asked questions
What happens if I click before it turns green?
That's a false start — no time is recorded, and the same round restarts with a new random wait. It doesn't count as a fast reaction, since you'd have been reacting to nothing.
Why does the wait time vary each round?
On purpose — a random delay stops you from timing your click to a predictable rhythm rather than genuinely reacting to the colour change.
What's a good reaction time?
Most people average somewhere in the low-to-mid 200s (milliseconds). Under 200ms consistently is quite fast; over 350-400ms is more typical for a first attempt or when distracted.
Why is the average tracked instead of my single best click?
A single click has a lot of natural variance — one lucky fast click doesn't say much on its own. The average across five rounds is a much more stable measure of genuine reaction speed to chase as a personal best.
Can I play on a phone?
Yes — tap instead of clicking; the same rules and timing apply.