Reaction Time Test
Click when the box turns green. Five rounds, instant average — free and entirely in your browser.
What is a Reaction Time Test?
A reaction time test measures how quickly you respond to a visual signal — here, the moment a red box turns green. The delay before each change is random (2–5 seconds), so anticipating the rhythm doesn't work; clicking early cancels the round. You get five valid rounds, then your average and best time in milliseconds. Everything runs in your browser: no sign-up, and your scores never leave your device.
How to Test Your Reaction Time
- Click the box (or press Space) to start.
- Wait while the box is red — the delay is random on purpose.
- The instant it turns green, click or press Space as fast as you can.
- Repeat for five rounds and read your average and best time in milliseconds.
100% Free — No sign-up, no email. The test runs entirely in your browser — nothing you do here is sent to a server.
Reading your score honestly
Browser tests measure your reflexes plus your hardware. Display refresh, input device, and the browser’s event loop each add delay that laboratory equipment doesn’t have, which is why online scores typically read tens of milliseconds higher than the 200–300 ms averages reported in research settings. The useful comparisons are your own attempts on the same device — time of day, sleep, and caffeine show up clearly across repeated runs.
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Frequently asked questions
- What is an average reaction time?
- Published studies of simple visual reaction time in young adults commonly report averages in the 200–300 ms range. Online tests like this one usually read 20–70 ms higher than laboratory equipment, because your monitor, input device, and browser each add delay before the click is registered — so compare your score against other people on the same kind of test, not against lab figures.
- Is my score affected by my monitor and mouse?
- Yes, meaningfully. A 60 Hz display can add up to ~17 ms just waiting for the next frame, wireless mice add several more, and browsers process input in ticks. That overhead is roughly constant per device, so the test is still good for comparing your own attempts — but a score difference between two people on different hardware can be mostly hardware.
- Can I improve my reaction time?
- Within limits. Practice on a specific task reliably improves performance on that task, and being rested, alert, and caffeinated measurably helps. Baseline simple reaction time, however, is largely physiological and declines gradually with age — no training turns 280 ms into 150 ms.
- Why does clicking too early reset the round?
- Because a click before the color change is a guess, not a reaction — the delay before green is random precisely so that timing the rhythm doesn't work. Counting early clicks would reward guessing and make every score incomparable.
- Keyboard or mouse — which is faster?
- Usually the keyboard, by a small margin: key travel is shorter than a mouse button's and there is no pointer involved. This test accepts both a click and the space bar, so you can measure the difference on your own hardware instead of taking anyone's word for it.
- Is this test free, and is anything tracked?
- Free, no sign-up, no email. The entire test runs in your browser — your scores are never sent to a server and disappear when you leave the page.