Reaction Time Test

How to use this tool

Wait for GO, then respond. Complete five valid rounds to get a median that is less affected by one unusually slow response than a single-round result.

1. Press Start round and wait for the signal. Responding before GO does not count.
2. Click, tap or press Space when GO appears. Keep using the same input method.
3. Finish five rounds, then compare the median with another five-round set on the same device.

How the median works

Put five response times in order and take the middle one. For example, 210, 220, 230, 240 and 600 milliseconds gives a median of 230 milliseconds. The slow final round does not pull the median up as much as it would pull up an average. A lower completed five-round median becomes your personal best.

What the number includes

The result includes screen refresh, the input device, browser scheduling and your response. Changing from a mouse to a touch screen changes more than your reaction. Close other busy tasks and compare like with like. This is a browser game, not a medical or diagnostic test, and it does not establish an overall ability score.

Your progress and privacy

No account is needed. Personal bests, preferences and saved progress stay in this browser where supported. They do not sync between devices. Keyboard and mouse test events are never saved. You can clear saved activity from the home page; the privacy notice explains consent and measurement.