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Loop length calculator: bars to seconds, samples and delay times

Bars to seconds and samples for a clean loop, plus delay times in ms.

Free · no accountRuns in your browser · nothing is uploaded

Loop length

20 to 300, decimals allowed.

Whole bars, 1 to 64.

Tempo counts quarter notes, as in a DAW, so a 6/8 bar is three quarter notes long.

Seconds
13.714
mm:ss.mmm
00:13.714
Beats
32
quarter notes
Samples
604,800
exact at 44.1 kHz

Stereo WAV size

2.3 MB at 16-bit · 3.5 MB at 24-bit

Fits ColabLoop's upload checks

Between 10 and 60 seconds and under 30 MB as a 24-bit stereo WAV.

Delay and reverb times at 140 BPM

Press a value to copy it. Hz is the LFO rate that repeats once per note.

Delay times in milliseconds and LFO rates in hertz for each note value at 140 BPM
NoteStraightDottedTriplet
1/1
1/2
1/4
1/8
1/16
1/32

Reverb starting points

  • Tight room · drums, plucks

    Pre-delay Decay

  • Plate or hall · vocals, snares

    Pre-delay Decay

  • Big space · pads, transitions

    Pre-delay Decay

Common starting points, not rules: pre-delay of a small fraction of a beat so the dry hit lands first, and a decay tied to the beat so the tail clears before the next one. Set by ear.

How it works

A loop that repeats cleanly is a whole number of bars, so its length follows from the tempo: seconds = bars x beats per bar x 60 / BPM. Eight bars of 4/4 at 140 BPM is 8 x 4 x 60 / 140 = 13.714 seconds.

The sample count multiplies that by the sample rate. When it is not a whole number, a bounce has to round the end, and the page shows by how much. Sizes are for a stereo WAV: a 44-byte header plus sample rate x bytes per sample x 2 channels x seconds.

The delay table uses a quarter note of 60,000 / BPM milliseconds. A dotted note is 1.5 times a straight one and a triplet is two thirds of it. Nothing is sent anywhere: the sums run in your browser, and the link in the address bar just carries your settings so you can share them.

Questions

How long is 8 bars at 140 BPM?
13.714 seconds in 4/4. Eight bars is 32 beats, and at 140 BPM each beat lasts 60 / 140 = 0.4286 seconds. At 44.1 kHz that is exactly 604,800 samples.
How do I work out how many bars fit in a number of seconds?
Divide the seconds by the length of one bar: bars = seconds x BPM / (60 x beats per bar). For a 30-second loop at 120 BPM in 4/4 that is 30 x 120 / 240 = 15 bars. A result that is not a whole number means the loop would end part-way through a bar.
Why does the sample count have decimals?
Audio is stored in whole samples, but a tempo like 128 BPM does not always give a bar that is a whole number of samples at 44.1 kHz or 48 kHz. The calculator shows the exact figure and how far the rounding moves the end. On one pass it is far too small to hear, which is why it only matters for very long exports.
Is a 6/8 bar six quarter notes?
No. Tempo here counts quarter notes, as it does in most DAWs, and a 6/8 bar holds six eighth notes, which is three quarter notes. At 120 BPM one bar of 6/8 lasts 1.5 seconds.
What are the delay times for?
Set a delay plugin's time by hand to the millisecond value, or use it to check a tempo-synced setting. The Hz column is the matching rate for an LFO or tremolo that should repeat once per note. The reverb figures are common starting points to adjust by ear.

The full guide

How long should a loop be? Bars, seconds and sample counts →

How many bars a loop should be, common lengths by genre, why the exact sample count matters for seamless looping, and delay times that match your tempo.

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