Time Signature Calculator — Bar Length & Song Time

The top number is beats per bar. The bottom number is the note value of each beat (4 = quarter note, 8 = eighth note, 2 = half note). So 4/4 means 4 quarter-note beats per bar. 6/8 means 6 eighth-note beats per bar (usually felt as 2 groups of 3).

4/4 is by far the most common, used in virtually all pop, rock, electronic, hip-hop and R&B music. 3/4 (waltz time) is the second most common. 6/8 is popular in ballads and folk music. Odd time signatures like 5/4 and 7/8 are used in progressive rock and jazz.

BPM traditionally refers to quarter-note beats per minute. In 4/4, each beat is a quarter note, so 120 BPM = 120 quarter notes per minute. In compound meters like 6/8 the felt beat is usually a dotted quarter (3 eighth notes), but this calculator always treats BPM as quarter-note BPM (the DAW/MIDI convention): 120 BPM in 6/8 here gives an eighth note of 250 ms — 240 eighth notes per minute. If your tempo is marked as "dotted quarter = X", enter BPM = 1.5 × X (e.g. dotted quarter = 80 → enter 120 BPM).

A typical pop song at 120 BPM in 4/4 is about 80-120 bars (2:40-4:00). A verse might be 8-16 bars, a chorus 8-16 bars. An intro and outro are typically 4-8 bars each. Electronic music tracks are often 64-128 bars (2-4 minutes) with longer buildups.