Reaction Time Test

Complete five visual trials

Start the test, wait while the target is yellow, and click only when it turns green. An early click is marked as a false start. Five valid trials produce an average.

What the number measures

The displayed milliseconds span from the browser drawing the ready state to the click event reaching page code. That interval includes perception, decision, movement, device processing, operating-system scheduling, browser work, and display timing. It is not a pure measurement of nerves or muscles.

Worked example

Five trials of 240, 221, 235, 229, and 225 milliseconds average 230 milliseconds. The average is more useful than selecting only the fastest trial because a lucky anticipation or scheduling difference has less influence. This page stores the lowest five-trial average as the personal best.

Why results vary

Attention, fatigue, expectation, input device, hand position, display refresh, wireless delay, background activity, and browser scheduling can all change a trial. The wait is randomized so the green state is harder to predict, but repeated use can still change strategy. Compare sessions on the same setup and look at several averages.

False starts

Clicking before green cancels the trial rather than recording an unrealistically fast result. Anticipation is part of many real tasks, but it would obscure the simple visual-response measurement here. Restart after a false start and wait for a clear color change.

Privacy and limitations

Trial values remain in the page; only the best average may be kept in local browser storage. No camera, microphone, account, profile, or public leaderboard is used. Results are casual feedback, not a neurological, vision, driving, gaming, occupational, medication, or fitness assessment. Seek qualified guidance for health or safety concerns.