Turn on sound, pick slow (90 BPM), medium (120 BPM) or fast (150 BPM), and start. Listen to four count-in beats, tap along for eight, keep going for sixteen silent beats, then continue as the accompaniment returns for four beats. Tap the pad or focus it and use Space or Enter. A round takes about 21, 16 or 13 seconds depending on the tempo.

Tempo change compares the median gap between your taps during the silence with your own median gap while following the accompaniment. The curve lines each silent tap up with where the beat would have been, counting from your last tap with the accompaniment, so you can see which beat you started drifting on and how far apart you were when it came back. Beat-to-beat wobble shows how much the silent gaps varied. If too few usable taps remain, or any gap is far from one beat, no result is given: the tool cannot reliably tell a missed tap from an intentional change of pace.

It does not measure your device's physical latency. Comparing intervals reduces the effect of a fixed timing offset, but changing audio, Bluetooth or input delays can still affect the round. Use the same device and audio setup throughout. This is a short rhythm game, not a diagnostic test or a population ranking.

A flashing light or a countdown would give you another rhythm to follow. The silent stretch leaves you with your own timing. Afterwards, the two tracks and audio replay let you compare the original pulse with your recorded taps.

An interrupted round is cancelled instead of scored; return to the page and start again. Tap times stay in this page’s memory and are not uploaded. The only thing kept is one steadiest result per tempo (two numbers: tempo change and how far off you were when the beat returned), stored in this browser on this device so the lobby can show it. Clearing your browser’s site data removes it.