BPM Explained
Tap Lab reports a stream pace using a stated convention: four taps per musical beat. These are quarter-beat intervals, often described as sixteenth-note spacing in common time. A musical quarter-note beat does not mean four beats per tap.
The calculation
Stream BPM = 60,000 ÷ (average tap interval in milliseconds × 4)
Equivalently: stream BPM = taps per second × 15.
| Tap spacing | Taps / second | Stream BPM |
|---|---|---|
| 250 ms | 4 | 60 |
| 125 ms | 8 | 120 |
| 100 ms | 10 | 150 |
| 75 ms | 13.33 | 200 |
Why at least two taps?
A single tap has no interval. Two accepted taps create one gap. Eleven evenly spaced taps from 0 to 1,000 ms create ten 100 ms gaps: the stream pace is 150 BPM. Tap Lab averages the accepted within-session gaps; it does not treat the first tap as an extra elapsed interval.
Stream pace versus full-window pace
Stream pace uses the time from tap to tap and therefore excludes silence after the final tap. Full-window pace instead divides all accepted taps by the full active test duration and multiplies by fifteen. It includes rests during that duration. For example, 80 taps in a ten-second test gives a full-window pace of 120 BPM.
Use full-window pace when comparing how many taps you sustained over equal-duration sessions. Use stream pace to understand the spacing of the taps you actually made. Neither number is a prediction of an osu! score.
Pauses
Paused time is excluded from the test duration. The first tap after a manual resume starts a new segment; no interval is measured across the pause. A resumed target-tempo segment also has a new first-tap reference.
Different patterns, different meanings
A beatmap can contain notes spaced at many different subdivisions. The same finger rate would describe a different musical BPM at two taps per beat. Tap Lab always uses four, so compare results only when the same convention is used.