⚡ Reaction Time Test
Measure exactly how fast your brain and fingers respond: click the moment the screen flashes green, get your time in milliseconds, and see where you rank.
About
Reaction time is the interval between a stimulus appearing and your voluntary response to it. For most healthy adults, visual reaction time falls between 150 ms and 300 ms, with trained athletes often landing under 200 ms. This tool presents a random-delay countdown before the screen turns green, preventing anticipation cheating — clicking before the green flash counts as a false start and fails the round. After each valid click the tool records your time, updates your session best, and assigns a letter grade (S, A, B, C, D) based on established human-reaction benchmarks. A shareable result card lets you compare scores with friends. Everything runs in the browser with no data sent anywhere.
How to use
- Click the start button to begin a round. The screen will show a red waiting state.
- Wait for the screen to turn green — the delay is random so you cannot predict it.
- Click (or tap) the instant you see green. Your reaction time in milliseconds appears immediately.
- Review your grade, last time, and session best. Repeat rounds to improve your score.
- Tap the share button to generate a result card and send your best time to friends.
FAQ
- What is a good reaction time?
- The average for healthy adults is around 200–250 ms. Under 200 ms is excellent; under 150 ms is exceptional and rare outside elite athletes.
- Why did clicking early fail the round?
- Clicking before the screen turns green means you were anticipating, not reacting. The test measures genuine reaction time, so early clicks are counted as false starts and the round is voided.
- Does using a mouse vs. a touchscreen affect my score?
- Yes, slightly. Touchscreens register input faster than mice in most browsers, so mobile taps often read 10–30 ms quicker. Compare scores using the same input method for consistency.
- How is my grade calculated?
- Grades are assigned based on your best time: S (under 150 ms), A (150–199 ms), B (200–249 ms), C (250–299 ms), D (300 ms or above). The grade reflects your fastest recorded click in the session.
- Is my data saved between sessions?
- Your best time is saved in your browser's localStorage and persists until you clear site data. No data is ever sent to a server.