Speed · Test
Wait for the signal, then respond as fast as you can. Five clean trials, median score.
No account. No tracking. Your results stay with you.
Ready when you are.
Wait for the panel to turn bright, then respond. One practice trial, then five scored trials.
Needs to see a colour and shape change on screen. Respond with a mouse click, a tap, or Space.
Each trial starts with a waiting period of a secure random length between 1.5 and 4.5 seconds, so the moment can't be predicted. Then the panel turns bright, a solid circle appears and the word “Now!” is shown — colour, shape and text change together.
The signal is drawn inside an animation frame and its onset time is read in that same callback with performance.now(). Your response time comes from the input event's own high-resolution timestamp, so the measurement doesn't depend on how busy the page is when it handles your press.
The first trial is practice and is never scored. Then five scored trials are collected. A press before the signal is a false start (“Too soon.”); it isn't counted and the trial is repeated. If the page is hidden or the window loses focus during a trial — or the browser stalls for more than 250 ms while the signal is showing — that trial is discarded and repeated.
score = median(RT₁ … RT₅) RT = response timestamp − signal onset (ms) spread = slowest − fastest
The median of the five valid trials is your score — it isn't pulled around by one unusually slow or fast trial the way an average is. Best, worst, spread, mean and the number of false starts are shown too.
Responses under 100 ms after the signal are treated as guesses rather than reactions and repeated (they are shown, never silently dropped). A trial with no response within 3 seconds times out and is repeated.
The test runs entirely in this browser tab. Results are saved only in this browser's local storage so you can compare with yourself — never uploaded, never tracked. You can clear them any time.