Click as soon as the box turns green. 5 rounds, we'll average it out.
Click to startRound 1 of 5
—average ms
—best ms
—worst ms
How it works
Each round waits a random 1.5-to-4.5-second delay — so you can't anticipate the exact moment — before turning green and recording a timestamp with performance.now(), a sub-millisecond clock separate from ordinary wall-clock time. Clicking before it turns green is flagged as "too soon" and doesn't count as a score. After 5 rounds it reports your average, best, and worst time.
FAQ
Why doesn't clicking too early just count as a very fast reaction?
Because it isn't a real reaction — a click during the red "wait" phase is caught before the green trigger fires and just makes you retry that round, rather than rewarding an early guess with a fake score.
Why might my result here differ from a physical reflex test?
This measures visual perception plus a browser click, which adds a few milliseconds of input and display latency on top of raw neurological reflex — it's consistent for comparing your own rounds, not a clinical measurement.
Free, unlimited, no account. If this saved you a paid tool, a small thanks is appreciated.