Reaction Time Test — Measure Your Click Reaction and Share the Result

With a mouse most people land between 200 and 300 ms, because that is roughly how long it takes a person to see light and move a finger. Frequent gamers often sit at 180-220 ms, and tapping on a phone tends to come out 20-50 ms slower because touch detection is added on top. Anything under 100 ms almost certainly means you guessed when the green would appear.

Not as an absolute value. Anything measured in a browser also contains the refresh rate of your monitor (up to 16.7 ms at 60 Hz), the polling interval of your mouse or keyboard, and the compositing delay of your operating system. The same person at the same moment scores faster on a 144 Hz gaming monitor than on a laptop screen. So comparing across devices means little; comparing yesterday and today on the same device is the useful comparison. This tool anchors the measurement as close as it can to the moment the screen was actually painted, which reduces the error but cannot remove those delays.

One round is luck. A single blink already takes more than 100 ms, so if the signal lands right then the whole score is ruined. In the other direction, if the wait drags on and you press early on a hunch that happens to be right, you get a number faster than human reaction allows. Averaging five rounds cancels much of both. The wait is drawn at random between 1.2 and 4.5 seconds each time, so there is no rhythm to memorise.

Yes. The measuring panel is a real button, so Space or Enter works, and on a phone you simply tap the screen. Each input method has its own delay, though, so do not compare mouse, keyboard and touch scores against each other. For anyone who has trouble telling the colours apart, the wording inside the panel changes too — "Wait" and "Press now!" — and the state is announced to screen readers.

In this browser only. Your nickname and the averages of your last ten runs stay in this device storage, and nothing is sent to a server. That is also why there is no global leaderboard — as long as the number is produced in a browser it can be faked, and a leaderboard nobody can police is worse than none. To clear your records, delete this site data in your browser.

Only the nickname you typed, your average and grade, the five individual times, the date you measured, and the address of this page. You can check exactly what it contains in the preview above the buttons. The image is drawn inside this browser and goes nowhere until you press Save, Copy or Share yourself.