How tap tempo calculator works
Tap any key or button in time with the music and the tool measures the milliseconds between each tap. Ten taps give nine intervals; the tempo is 60000 divided by the average interval, because a tempo is just a beat duration expressed as beats per minute. Tap four times at exactly half-second spacing and the answer is 120 BPM.
The headline BPM is the mean of all intervals so far, which sharpens as you add taps — early taps wobble, but averaging damps their influence. A median BPM is shown alongside, since a single stray tap (a late click, a phone buzz) drags the mean while leaving the median nearly unmoved. When the two agree closely, you have the tempo; when they diverge, keep tapping.
A jitter percentage — the spread between your fastest and slowest interval as a share of the average — tells you how steady the tapping is. Under about 5% is a solid lock. Reset clears everything and starts a new song; there is no need to be precise about the first tap, only consistent about the ones after it.