How the test works
- Click the panel to start. It turns red.
- At a random moment between 1.5 and 4 seconds, it turns green. Click as fast as you can. Tapping the screen or pressing the Space bar works too.
- If you click before it turns green, you get "Too soon!" and that round is repeated.
- After 5 rounds you see your average, fastest and slowest times, and a rating.
Ratings
| 5-round average | Rating |
|---|---|
| Under 200 ms | Very fast |
| 200–250 ms | Fast |
| 250–300 ms | Average |
| 300 ms or more | Slow |
These bands are a common rule of thumb for simple visual click tasks, not a medical measure. Your own results can vary quite a bit with fatigue and focus.
Why your device matters
The number you see includes device delay, not just your reflexes. A 60 Hz screen redraws about every 16.7 ms, so the green can appear up to that much later than the moment it was triggered, and wireless mice, Bluetooth keyboards, and touchscreens add input lag of their own. To compare scores fairly, use the same device and the same input method. Timing uses performance.now() and is shown in whole milliseconds.
Your personal bests (single best and best 5-round average) are stored only in this browser and never sent to a server. If you just need to time something, try the Timer & Stopwatch.