Measure your reaction time over several attempts and take the median as your score.
Calculations happen locally. We do not send your values to our server.
For attempts of 250, 231, 262, 420 and 244 ms, the mean is 281.4 ms because of the slow try, while the median is 250 ms and represents typical performance much better.
Press Start, wait while the button says Wait, and click as soon as it changes to Click!. The delay before the change is random, between one and four seconds, so you cannot succeed by learning a rhythm, and the elapsed high-resolution time from the change to your click is recorded.
The measurement includes more than your nervous system: screen refresh, display processing, mouse or touchscreen latency and browser timing all add delay. This is a casual test for comparison over time on the same setup, not a medical or driving assessment.
Press Start, wait while the button says Wait, and click as soon as it changes to Click!. The delay before the change is random, between one and four seconds, so you cannot succeed by learning a rhythm. Clicking during the waiting period counts as too early and cancels that attempt, and switching away from the tab cancels an attempt in progress. After five valid attempts the result shows the median time and your fastest time in milliseconds.
A single distracted attempt can distort an average. For attempts of 250, 231, 262, 420 and 244 ms, the mean is 281.4 ms because of the slow 420 ms try, while the median, the middle value after sorting, is 250 ms and represents typical performance much better. The fastest time, 231 ms here, is shown separately. If your attempts cluster tightly, such as 290 to 310 ms, the median of 300 ms and the fastest time will be close together.
The time includes more than your nervous system. Screen refresh, display processing, mouse or touchscreen latency and browser timing add delay, so the same person can score differently on another device. Wireless mice, high-latency televisions and battery-saving modes tend to add time; a wired mouse and a high-refresh monitor reduce it. Tiredness, caffeine and practice also change results. This is a casual test for comparison over time on the same setup, not a medical or driving assessment.
| Input | Result |
|---|---|
250 · 231 · 262 · 420 · 244 ms | median 250 ms · fastest 231 ms |
250 · 231 · 262 · 420 · 244 ms · mean | 281.4 ms |
300 · 310 · 290 · 305 · 295 ms | median 300 ms · fastest 290 ms |
wait before “Click!” | 1–4 s, random |
Because a single distracted attempt can distort an average, and the median, the middle value after sorting, ignores that outlier. If your attempts cluster tightly, such as 290 to 310 ms, the median of 300 ms and the fastest time will be close together, which tells you the result is stable.
Clicking during the waiting period counts as too early and cancels that attempt, which stops guessing from producing an impossibly fast score. Switching away from the tab also cancels an attempt in progress, because the browser stops updating the page reliably while it is hidden.
Because the equipment is part of the measurement. Wireless mice, high-latency televisions and battery-saving modes tend to add time, while a wired mouse and a high-refresh monitor reduce it. Tiredness, caffeine and practice also change results, so compare only on the same hardware.