Tool
Song length calculator
Enter bars, tempo, and meter. The duration is seconds = bars × beats per bar × (60 / BPM). The result is shown as mm:ss and as seconds. No audio file is loaded.
When to use song length
Use this calculator when you know how many bars you will play, and you need a clock time: an intro, a loop, or a practice excerpt. The formula does not listen to a recording.
Beats per bar come from the meter. 4/4 uses 4, 3/4 uses 3, and 2/4 uses 2. 6/8 uses 2, because this site counts two dotted-quarter pulses in each 6/8 bar.
Empty bars, zero bars, empty BPM, or 0 BPM show an error on the field. The page will not print Infinity.
To go the other way, from a duration back to bars, use bars and time.
Worked examples
32 × 4 × (60 / 120) = 64 seconds, shown as 1:04. Is that the length of the passage you meant to loop?
16 × 3 × (60 / 90) = 32 seconds. Does a 16-bar waltz at 90 sit in about half a minute?
8 × 2 × (60 / 100) = 9.6 seconds. Would counting six eighths have given a different clock time? On this page it would, so the 6/8 rule stays fixed.
Questions
What is the exact formula?
The formula is seconds = bars times beats per bar times (60 / BPM). 4/4 has four beats, 3/4 has three, 2/4 has two, and 6/8 has two dotted-quarter beats.
Why not count six eighths in 6/8?
You could, if BPM meant the eighth note. This tool treats BPM as the conducted pulse, so 6/8 has two beats. The 6/8 guide explains the choice.
Does this measure a finished mix?
No. The calculator uses the numbers you enter. It does not read a file and it does not host recordings.