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BPM and Delay Time Calculator

Calculators · Added

A delay set by ear is a delay you have to reset every time the tempo changes. Enter the BPM and get the millisecond value for every note division — straight, dotted and triplet — plus bar length and sensible reverb starting points.

Fractional tempos are fine — plenty of tracks sit at something like 127.5.

Try:

Result

One beat

500.00 ms

120 BPM · 2,000.00 ms per bar of 4 · Moderato — moderately

Quarter note
500.00 ms

The beat itself

Eighth note
250.00 ms

The usual delay length

Dotted eighth
375.00 ms

The one that plays against eighth notes

One bar
2,000.00 ms

Every note value

NoteStraightDotted (×1.5)Triplet (×2⁄3)As a rate
Whole note12,000.00 ms3,000.00 ms1,333.33 ms0.500 Hz
Half note1/21,000.00 ms1,500.00 ms666.67 ms1.000 Hz
Quarter note (beat)1/4500.00 ms750.00 ms333.33 ms2.000 Hz
Eighth note1/8250.00 ms375.00 ms166.67 ms4.000 Hz
Sixteenth note1/16125.00 ms187.50 ms83.33 ms8.000 Hz
Thirty-second note1/3262.50 ms93.75 ms41.67 ms16.000 Hz
Sixty-fourth note1/6431.25 ms46.88 ms20.83 ms32.000 Hz

Reverb, as a starting point

Pre-delay — a 64th note
31.25 ms
Decay — one bar
2,000.00 ms
Decay — two bars
4,000.00 ms

Everything here comes from one division: 60,000 milliseconds over the tempo gives the length of a beat, and every other figure is that scaled by a note value. A dot adds half the note's own length again; a triplet fits three into the space of two. The dotted eighth is worth knowing by sight — set against straight eighth notes it produces the interlocking pattern that made U2's guitar sound, and it is the reason a delay preset that worked on one track is wrong on the next. The reverb figures are conventions rather than rules, and the ear beats them.

How to use the bpm and delay time calculator

  1. 1Enter the tempo in beats per minute. Fractional tempos are fine.
  2. 2Set the beats per bar if you are not in four.
  3. 3Find the note value you want in the table and take the millisecond figure.
  4. 4Use the pre-delay and decay suggestions as a starting point for reverb, then adjust by ear.

Examples

The reference tempo

Input
120 BPM in 4/4
Result
Beat 500 ms, bar 2,000 ms. Eighth note 250 ms, dotted eighth 375 ms, eighth triplet 166.67 ms, sixteenth 125 ms. Marked Moderato.

Reverb settings at that tempo

Input
Same 120 BPM
Result
Pre-delay 31.25 ms — a 64th note — with decay suggestions of 2,000 ms for one bar and 4,000 ms for two.

About the bpm and delay time calculator

One division, everything else follows

Every number on this page comes from a single calculation: 60,000 over the tempo. At 120 BPM that is 500 milliseconds per beat, and the entire table is that value multiplied or divided by powers of two, with two variations applied on top.

Knowing the arithmetic matters more than having the table, because it makes the relationships obvious. A delay that sounds right at 120 will be badly wrong at 128, and by a proportion you can work out in your head — the beat is about 6% shorter, so every delay figure needs to come down by the same amount.

Where synced timing is the wrong answer

Timing locked exactly to the grid is right for a rhythmic delay and wrong for several other things. A slapback echo on a vocal works because it is short and unsynchronised — around 80 to 120 milliseconds regardless of tempo — and locking it to a note value makes it disappear into the rhythm instead of thickening the voice.

Doubling effects behave the same way: what makes them convincing is precisely that the copy is not on the grid. And a delay tuned dead on the beat can leave a mix feeling stiff, which is why plenty of engineers set the synced value and then pull it a few milliseconds off. The table gives you the number to start from and to depart from deliberately.

Frequently asked questions

How is the millisecond figure worked out?
60,000 milliseconds divided by the tempo gives the length of one beat, since there are 60,000 milliseconds in a minute and the tempo counts beats within it. Every other figure in the table is that beat length scaled by the note value: an eighth note is half a beat, a sixteenth a quarter, a bar four beats in common time.
What makes the dotted eighth special?
It is three-quarters of a beat, so against straight eighth notes it never lands in the same place twice in a row until the bar comes round. The result is an interlocking pattern rather than an echo — the sound most associated with U2's guitar parts, and the reason a dotted-eighth delay is a standard preset rather than an obscure setting.
What do dotted and triplet mean?
A dot adds half the note's own length again, so a dotted note is one and a half times the straight one. A triplet fits three notes into the time two would normally take, making each two-thirds of the straight value. Both columns are given for every note value because reaching for either is far more common than working it out.
Why do the reverb figures come with a caveat?
Because they are conventions rather than derivations. Pre-delay of a 64th note and decay of a bar or two are widely used starting points that keep a reverb tail from smearing across the next chord, but nothing in the arithmetic says they are correct. A dense mix wants a shorter tail than the rule suggests and a sparse one can carry much longer.
What is the Hz column for?
It is the same figure expressed as a rate rather than a duration, which is what you need when a tempo-synced modulation is set in hertz instead of note values. At 120 BPM a quarter note is 2 Hz and an eighth is 4 Hz. It is also the bridge to setting an LFO or a tremolo to the tempo when the device offers no sync.

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