Reaction Time Tester
Wait for the screen to flash teal, then tap as fast as you can. Get your reaction time in milliseconds and build a class distribution chart to compare everyone's reflexes. Works offline.
Built by the AbraCalc team
How to play
- Tap the red panel to arm a round — it will hold on red for a random, unpredictable wait.
- The instant the panel flips to teal and says GO, tap it again as fast as you can.
- Your reaction time in milliseconds appears below, and a new bar is added to the class chart.
- Tap Clear Results to wipe the chart and start a fresh comparison for the next group.
Tap the panel and wait — it stays a warm red for an unpredictable stretch of time before flipping to teal, and the instant it does, tap again as fast as possible. The result appears in milliseconds, and every tap you make gets added to a running bar chart so a whole class can see their reaction times lined up side by side, with the fastest tap highlighted. Tap too early, before the color changes, and the panel flags it so that result doesn't count as a fair reading. It's built for a quick science lesson on human reflexes or just a friendly competition over who has the fastest hands in the room, and since everything runs locally in the browser, no results are ever saved or sent anywhere between taps.
Frequently asked questions
- What happens if I tap before the screen turns teal?
- The panel flags it as too soon and does not record a time, since tapping early doesn't measure a genuine reaction — tap the panel again to try that round over.
- How is the random wait time decided?
- Each round picks a fresh, unpredictable delay between about 1.2 and 4.5 seconds before the color changes, so there's no pattern to anticipate or memorize.
- Can a whole class use this to compare reaction times?
- Yes — every successful tap adds a new bar to the on-screen chart with the fastest result highlighted, so you can pass the device around and build up a class-wide comparison.