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Reaction Time Tester
Measure how fast you react. Wait for the panel to turn green, then click as quickly as you can — your reaction time in milliseconds is recorded for each trial. Click too early and it counts as a false start. Run several trials and see your mean, median, fastest, and consistency. Everything runs locally in your browser.
Click to start
A trial begins when you click here
| Trials | 0 | Valid | 0 | False starts | 0 |
|---|---|---|---|---|---|
| Mean | — | Median | — | Std dev | — |
| Fastest | — | Slowest | — | Rating | — |
Each trial: the panel turns red (wait), then after a random 1.2–4.2 s delay it turns green — click immediately. Reaction time is the delay between green and your click. Times under 100 ms are false starts (you anticipated the green); times over 1 s count as valid but inattentive. Reaction time naturally varies with age, fatigue, and stimulus; typical median is 200–300 ms. Runs locally — no data leaves your browser.