Loop Bar Length Calculator

Enter tempo, bars and beats per bar to get the loop length in seconds.

How it is calculated

The tool first finds how long one beat lasts, then multiplies by the number of beats in the loop: beat = 60 ÷ BPM and length = bars × beats per bar × beat. BPM is beats per minute, bars is the number of bars in the loop, and beats per bar is the top number of the time signature (4 for 4/4, 3 for 3/4, 6 for 6/8 counted as six beats). The result is in seconds and is shown to three decimals; the single beat length is shown to four decimals, along with the total beat count. Tempo, bars and beats must all be greater than zero, otherwise nothing is calculated. Fractional tempos such as 127.5 are accepted.

Worked example

A 4-bar loop in 4/4 at 140 BPM. One beat lasts 60 ÷ 140 = 0.4286 s. The loop holds 4 × 4 = 16 beats. Length = 16 × 0.4286 = 6.857 s. If you export the loop as an audio file, it should be about 6.857 seconds long (plus any reverb tail you want to keep).

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Common mistakes

  • Entering the number of beats in the loop instead of beats per bar: a 4-bar loop is bars = 4, beats = 4, not beats = 16.
  • Using the bottom number of the time signature. For 3/4 the value is 3, for 7/8 it is 7 (counting eighth notes), and the BPM must then refer to the same note value.
  • Mixing up half-time and double-time: a track felt at 70 BPM may be written as 140 BPM in the DAW, which halves the loop length.
  • Expecting the length to include reverb or delay tails. The result is only the musical length of the bars.

About this calculator

In music production, a loop's duration in real time depends entirely on tempo: at a given BPM (beats per minute), one beat lasts 60 ÷ BPM seconds, so a loop spanning a certain number of bars and beats-per-bar lasts (60 ÷ BPM) × beats-per-bar × bars seconds. This is why the same 4-bar drum loop feels dramatically shorter at 174 BPM (drum and bass) than at 90 BPM (hip-hop), even though it's the identical musical length in bars.

This calculator takes the tempo, number of bars, and beats per bar, and returns the loop's exact length in seconds. Music producers and DJs use it to time-stretch or trim samples to fit precisely into a DAW's timeline, sync a loop to a video cut, or match two loops recorded at different tempos so they align perfectly when layered.

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Comments (1)

  • Editorial team

    Check that your DAW tempo and the loop agree before cutting audio. At 140 BPM a four-bar 4/4 loop is 6.857 s, but if the track is really felt at half tempo, the same bars last 13.714 s at 70 BPM. Sample trims that are off by a few milliseconds will drift when the loop repeats, so use the three-decimal figure rather than a rounded one. What tempo range do you usually work in?

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