Reaction Time Test
Wait for the panel to turn green, then click or press space as fast as you can — five rounds, then your average and best times.
Benchmark: simple visual reaction time averages roughly 200–280 ms in published studies. Your score includes your screen and input latency, so compare runs on the same device.
How it works
- Click the panel (or press space) to start; it turns red while you wait for a randomized delay of 1.5 to 5 seconds.
- The moment the panel turns green, click or press space as fast as you can — clicking during the red phase does not count and simply restarts that round.
- Complete five valid rounds to see your average, your best time, the full list of attempts, and how you compare to the typical human range.
Frequently asked questions
- How does the reaction time test measure milliseconds?
- The timer starts the instant the panel turns green and stops on your click or key press, using the browser’s high-resolution performance clock rather than the ordinary system clock. The waiting delay before each round is drawn from a cryptographically random source between 1.5 and 5 seconds, so you cannot anticipate the pattern.
- What is a good reaction time for a human?
- Laboratory studies of simple visual reaction time typically report averages around 200 to 280 milliseconds for healthy adults, with trained gamers and athletes sometimes landing below 200 ms. Scores above 300 ms are still perfectly normal, especially on a phone, when tired, or later in the day.
- Why is my score slower on this test than my real reflexes?
- Every result includes hardware latency you cannot remove: your screen takes time to show the green frame and your mouse, touchscreen, or keyboard takes time to register the input. This overhead is commonly 20 to 60 ms combined, so treat the numbers as comparable to other browser tests, not to lab equipment.
- Does clicking too early ruin my whole run?
- No. If you click while the panel is still red, that round is cancelled with a reminder and you simply retry it — the attempt is not recorded and no penalty is added to your times. Only five valid green-panel clicks count toward your average and best.
- Is anything about my results uploaded or tracked?
- No. The entire test runs locally in your browser: the random delays, the timing, and the statistics are all computed on your device and nothing is sent to a server. Refreshing the page clears the results completely.
About this tool
This reaction time test measures how quickly you respond to a visual signal. Click the panel to arm a round: it turns red while you wait, then — after an unpredictable delay of 1.5 to 5 seconds — flips to green. Your job is to click, tap, or press the space bar the instant you see green. After five valid rounds the tool shows your average, your fastest single time, and every individual attempt, along with an honest comparison against the commonly cited human range.
Everything happens in your browser. The delay before each round is generated with the Web Crypto API, so it is genuinely unpredictable and cannot be gamed by rhythm. Timing uses performance.now(), a monotonic sub-millisecond clock, started exactly when the green state is rendered and stopped on your pointer-down or key-down event — pointer-down rather than click, because a full click only registers on release and would inflate your score. If you jump the gun during the red phase, the round is cancelled and retried without recording a false time. No data leaves your device.
People use tests like this to warm up before competitive games, to compare input devices — a low-latency gaming mouse versus a laptop trackpad is often a measurable 20 to 40 ms difference — or simply to check how caffeine, sleep, or time of day affects alertness. Because conditions vary, the most meaningful comparison is against your own scores taken on the same device.
A few practical tips: keep your finger resting on the mouse button or space bar rather than hovering, watch the center of the panel instead of the whole screen, and close heavy background tabs that can delay rendering. Remember that monitor refresh rate and input latency add a fixed overhead to every attempt, so a 240 Hz display will genuinely score faster than a 60 Hz one for the same human.