How the reaction test works
Start a round and wait for the target to turn green. The delay is randomized so you cannot learn a fixed rhythm. The test records the time between the browser drawing the green state and receiving your click or tap. Early clicks are discarded.
Why five rounds?
Reaction time changes from trial to trial. Attention, anticipation, background activity, and individual frames can make one result unusually fast or slow. A five-round average reduces the influence of a single outlier without making the test exhausting.
- Use the same device and input method when comparing scores.
- Keep the tab visible and close heavy background applications.
- Complete a warm-up test before treating a score as representative.
Interpreting your result
An online result includes human response time plus display, browser, operating-system, and input delay. It is not a clinical measurement. Read what is a good reaction time and our explanation of device latency.