About

What this site is

Test My Reaction is a free, browser-based reaction time test. You click a panel, wait for it to turn green, and click again as fast as you can. We measure the time between the colour change and your click in milliseconds, run five rounds, drop the fastest and slowest for fairness, and tell you what percentile you sit in.

That is the whole product. There is no sign-up, no email collection, no ads inside the test zone, and no premium tier. Your scores are saved to your browser's local storage — nothing leaves your device. If you clear your browser data, your history is gone.

Why this site exists

Most reaction time tests on the internet fall into one of two camps. Either they are old, slow, and visually painful, or they are buried inside a multi-test "cognitive benchmark" hub that tries to upsell you on a brain training subscription. Neither serves the person who just wants a clean, honest number.

This site exists to be the third option. A single, well-built test that does one thing properly. No upsells, no pop-ups, no marketing copy pretending to be science. The percentile ranking is calibrated against published research. The methodology is transparent. The code is straightforward.

How the test works

The test uses your browser's high-resolution performance API to measure time between the colour change and your click. This API is accurate to microseconds in modern browsers, so the timing itself is essentially perfect. The main source of error is your hardware — mouse latency, monitor refresh rate, and operating system scheduling all add a few milliseconds.

The five-round format with trimmed mean is borrowed from humanbenchmark and the wider reaction time research tradition. Single attempts are noisy — your fastest round might be a lucky anticipation click, your slowest might be a momentary distraction. Dropping both and averaging the middle three gives a more stable result that better reflects your actual reaction speed.

The percentile ranking is calibrated against a log-normal distribution fitted to a mix of academic studies (Luce 1986, Welford 1980, Silverman 2006 age meta-analysis) and the aggregated public data from major web RT tests. The result is a percentile rank that should be roughly comparable across sites, with the usual caveat that your hardware affects your absolute score.

What we don't do

• We don't collect accounts or emails.
• We don't sell your data.
• We don't run ads inside the test zone (only on informational pages, if any).
• We don't claim reaction time is a measure of intelligence, fitness, or anything else.
• We don't give medical advice. If you're worried about your reaction time, talk to a doctor.

Who built this

Test My Reaction is built and maintained by a small team interested in cognitive measurement, web performance, and clean design. The site runs on Next.js and deploys as a static site on Cloudflare Pages — no servers, no databases, no analytics tracking your every move.

If you have feedback, found a bug, or want to suggest a feature, head over to the contact page and send us a note. We read everything, even if we can't respond to all of it.