tempocalculator

Bars to Time Calculator: Song Length From BPM

16 bars of 4/4 at 120 BPM last 32 seconds. Enter a tempo, 1 to 10,000 bars and one of nine time signatures, and the calculator gives the duration in minutes and seconds, the total in seconds and the length of one bar. The second form works backward: at the same settings, 3 minutes 30 seconds holds exactly 105 bars.

Any tempo from 20 to 300 BPM, to two decimal places.

Duration

0:27.43

minutes : seconds

16 bars of 4/4 at 140 BPM last 27.43 seconds. One bar lasts 1,714.29 ms.

duration = bars × beats per bar × (4 ÷ beat unit) × 60 ÷ BPM

How many bars fit a length?

At the tempo and time signature above, 3:30 holds 122.5 bars (122 complete).

How is the length of a section calculated?

Multiply the number of bars by the length of one bar. One bar lasts beats per bar × (4 ÷ beat unit) quarter notes, and a quarter note lasts 60 ÷ BPM seconds.

duration (s) = bars × beats per bar × (4 ÷ beat unit) × 60 ÷ BPM

The beat unit matters because BPM counts quarter notes. A 6/8 bar holds six eighth notes, which equal three quarter notes, so at 120 BPM it lasts 1.5 seconds. A 2/2 bar holds two half notes, four quarter notes, the same as 4/4. The time signatures explainer covers what the two numbers mean.

The reverse form divides a target length by the bar length: bars = seconds ÷ bar length.

How to use the calculator

  1. Set the tempo

    Enter the BPM, or use the slider and steppers.

  2. Enter the bars

    Type a whole number from 1 to 10,000 in Number of bars.

  3. Pick the time signature

    Choose 2/4, 3/4, 4/4, 5/4, 6/8, 7/8, 9/8, 12/8 or 2/2.

  4. Read the duration

    The Duration panel shows minutes : seconds to two decimals; the sentence below adds total seconds and one bar in milliseconds.

  5. Or fit bars into a length

    Under How many bars fit a length?, enter Minutes and Seconds. The result uses the tempo and signature above and gives total and complete bars.

Worked examples: typical sections and songs

Tempo and meter both change how long a section lasts. Every row is computed with the tool's formula.

Durations of sections at different tempos and meters
SectionTempo and meterOne barDuration
8-bar intro120 BPM, 4/42,000 ms0:16.00
32-bar build128 BPM, 4/41,875 ms1:00.00
24-bar waltz verse90 BPM, 3/42,000 ms0:48.00
16-bar groove140 BPM, 7/81,500 ms0:24.00
64-bar drop174 BPM, 4/41,379.31 ms1:28.28
100-bar song95 BPM, 4/42,526.32 ms4:12.63

Working backward, a 3-minute radio edit at 128 BPM in 4/4 holds exactly 96 bars, and 30 seconds at 100 BPM holds 12.5 bars, so 12 complete bars.

Planning with bar counts

Bar counts turn an arrangement into a timeline. Songwriters check whether a draft fits a target length before recording. Composers for video find how many bars fill a 30-second spot at a chosen tempo, then adjust the BPM until the count is a whole number. DJs and producers plan 16- and 32-bar phrases so mixes change on phrase boundaries.

Once the length is set, the downloadable click track builds a WAV of the same number of bars for rehearsal or recording. Individual beat and note lengths for the same tempo are in the BPM to milliseconds table.

What the calculator assumes

One steady tempo and one time signature for all bars. Songs with tempo changes, ritardandos or mixed meters need each section calculated separately and added up. Pickup bars and fermatas are not counted. The Seconds field accepts 0 to 59.99, and results round to hundredths of a second.

Questions

How long is 16 bars at 90 BPM?

42.67 seconds in 4/4. One bar lasts 2,666.67 ms, and 16 of them make 42,666.67 ms.

How many bars are in a 3-minute song at 120 BPM?

90 bars of 4/4. 180 seconds ÷ 2 seconds per bar = 90.

Why does 6/8 give a shorter bar than 4/4 at the same BPM?

A 6/8 bar holds three quarter notes, not four. At 120 BPM it lasts 1,500 ms against 2,000 ms for 4/4.