BPM to Delay & Reverb Time Calculator

Understanding the BPM to delay time calculator — concept and principle

When a delay echo or a modulation effect is locked to the song's tempo, it sits inside the groove instead of fighting it. This calculator turns a tempo in beats per minute into the length of common note values in milliseconds, and the quarter-note rate in hertz for LFOs. Producers and live engineers use these numbers to set delay times, reverb pre-delay, compressor release and tremolo or filter-sweep rates on gear that has no tap-tempo or sync function.

Every delay time is a slice of the 500 ms beat at 120 BPM.

How it is calculated

One beat (a quarter note in 4/4) lasts 60,000 / BPM milliseconds, because a minute has 60,000 ms. Every other value is a fraction or multiple of that beat:

Eighth note = 30,000 / BPM (half a beat).
Sixteenth = 15,000 / BPM (a quarter of a beat).
Dotted eighth = 45,000 / BPM (an eighth plus half of an eighth, 1.5 × eighth).
Eighth-note triplet = 20,000 / BPM (three in the space of one beat).
Whole bar of 4/4 = 240,000 / BPM (four beats).
LFO rate at one cycle per quarter note = BPM / 60 Hz.

The principle

Tempo is a frequency: beats per minute. Converting to a period means taking its reciprocal and changing units, which is all 60,000 / BPM does. Musical note values are defined as simple ratios of the beat, so their times scale the same way. A dot adds half the value of the note, and a triplet squeezes three notes into the space of two, which is why the eighth triplet is two-thirds of an eighth. A delay set to these lengths makes each repeat land on a rhythmic subdivision, which the ear hears as part of the rhythm rather than as smearing.

Worked example

Input: 120 BPM.
Quarter note: 60,000 / 120 = 500 ms.
Eighth: 30,000 / 120 = 250 ms; sixteenth: 15,000 / 120 = 125 ms.
Dotted eighth: 45,000 / 120 = 375 ms.
Eighth triplet: 20,000 / 120 = 166.67 ms.
Whole bar: 240,000 / 120 = 2,000 ms; LFO rate: 120 / 60 = 2 Hz.

Each point is the calculator re-run with only “Tempo (BPM)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Tempo (BPM)	Quarter note (ms)
30	2,000
60	1,000
90	666.6666667
120	500
150	400
180	333.3333333
240	250

How to read the result

Longer values (quarter, bar) give spacious, clearly separate echoes suited to ballads and vocals; short ones (sixteenth, triplet) thicken the sound and add motion. The dotted eighth is a classic choice for rhythmic guitar delays because its repeats fall between the straight eighths. For reverb pre-delay, people often start with a short subdivision such as a 1/32 or 1/64 note so the dry attack stays clear. Halve the LFO rate for one cycle per half note, double it for one per eighth.

Common mistakes

Entering the half-time or double-time feel instead of the actual BPM, doubling or halving every value.
Assuming "beat" means a quarter note in compound meters such as 6/8, where the felt beat is a dotted quarter.
Entering milliseconds where a plugin expects seconds.

Keep in mind: These times are exact mathematically, but musical feel matters: many engineers shorten or lengthen a delay by a few milliseconds by ear, and the "whole bar" value applies only to 4/4.

Frequently asked questions

How do I get a dotted quarter delay?

Multiply the quarter-note value by 1.5: at 120 BPM that is 750 ms, or 90,000 / BPM in general.

What delay time works at 100 BPM?

A quarter note is 600 ms and an eighth 300 ms; a dotted eighth is 450 ms.

How do I convert a delay time back to BPM?

BPM = 60,000 / quarter-note time in ms. A 400 ms quarter-note delay matches 150 BPM.

Sources: B. Owsinski, The Mixing Engineer's Handbook

Checked 8 Nov 2026. Standard textbook formulas in SI units, computed in your browser. For learning and estimates — real designs must follow your local codes and be checked by a qualified engineer.

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