How to calculate a piece’s length
Enter the BPM, choose the note value counted by that BPM, enter the number of complete measures, and set the top and bottom numbers of the time signature. Calculate to see clock time, seconds, counted BPM beats, and written denominator notes.
Use the notated meter, not a guessed pulse. In 6/8, for example, there are six eighth-note units per measure. A conductor may count two dotted-quarter beats, but that is a different tempo-beat convention and must be represented explicitly.
Formula
Written notes = measures × numerator. BPM beats = written notes × BPM beat denominator ÷ time-signature denominator. Duration in seconds = BPM beats × 60 ÷ BPM.
For 32 measures of 4/4 at quarter-note = 120 BPM, there are 128 quarter-note beats. The duration is 64 seconds, shown as 1:04.
More examples
24 measures of 3/4 at 90 BPM
There are 72 quarter-note beats. At 90 per minute, the passage lasts 48 seconds.
16 measures of 6/8 with eighth-note = 120
There are 96 eighth-note beats, so the fixed-tempo duration is 48 seconds.
Assumptions and limits
- Every measure is treated as complete and uses the same time signature.
- The BPM remains constant from start to finish.
- Pickups, held final notes, rests outside the bar count, fermatas, repeats, and cuts must be added separately.
- The calculator does not upload, inspect, or analyze a recording.
Frequently asked questions
Why can the recorded song be longer?
Performances can include tempo changes, pauses, fermatas, count-ins, and endings that are outside a constant-tempo measure calculation.
How should I enter 6/8?
Use 6 as the numerator and 8 as the denominator, then separately select the note value counted by the BPM marking.