Tap the instant the screen turns green. Five rounds, one average, and where you rank against everyone.
On a computer, Space works too
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Space or Enter works too
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Comparing with everyone…
Simple visual reaction time, the time between seeing a signal and pressing, is about 200 to 300 milliseconds for most adults. Tests taken with a mouse average roughly 270 ms, while phones usually land in the 300s because touch input and the display add their own delay. This reaction time test averages five rounds, gives you a tier, and shows how you rank against everyone who has finished it.
Age matters: reaction speed peaks in the early twenties and slows gradually after that. So do sleep, fatigue, caffeine and focus. Hardware counts too. The same person scores faster on a 120 Hz screen or with a wired mouse than on an older phone in low-power mode.
Sleep well, rest your finger just above the screen, and don't try to guess when the light will change. React to the color, not the timing. Studies suggest action video games and fast ball sports can sharpen reaction speed over time. Take the test a few times and compare your best run.
The delay before green is drawn from a cryptographic random number between 1.5 and 4.5 seconds, so there is no rhythm to learn. Tapping before green is a false start and that round is repeated. Taps within 100 ms of green count as guesses, since no one can see and react that quickly. If you switch apps or tabs mid-round, or don't tap within 2 seconds of green, that round is thrown out and run again.
For simple visual reaction time, most adults fall between 200 and 300 ms. With a mouse the average is about 270 ms; on a phone, 300 to 350 ms is common because of touch and display delay. On this test, anything under 300 ms is faster than average.
Every device takes a little time to actually show the color and to register your tap or click, usually adding 10 to 80 ms to your result. High refresh rate screens (120 Hz and up) and wired mice or keyboards add the least. For a fair comparison, test on the same device.
Tapping before the screen turns green is a false start. Tapping within 100 ms of green also counts, because that is a guess rather than a reaction. The round is repeated, false starts never count toward your average, and the result screen shows how many you had.
Every finished test adds its average to a shared distribution in 10 ms steps. Your rank is the share of other players who were slower than you. Only the step number is stored, with no name or device information, and the ranking gets more accurate as more people play.
Get enough sleep, turn up screen brightness, and keep your finger close to the screen. Turning off low-power mode and closing other apps reduces device delay. Most of all, focus on the color change instead of trying to predict it.