Delay & Reverb Time Calculator
Turn any BPM into delay times in milliseconds and hertz for straight, dotted and triplet notes, plus reverb pre-delay and decay.
Updates as you type — the beat is a quarter note.
Delay times at 120 BPM
| Note | Straight (ms) | Dotted (ms) | Triplet (ms) | Straight (Hz) |
|---|---|---|---|---|
| 1/1 Whole note | — | — | — | — |
| 1/2 Half note | — | — | — | — |
| 1/4 Quarter note | — | — | — | — |
| 1/8 Eighth note | — | — | — | — |
| 1/16 Sixteenth note | — | — | — | — |
| 1/32 Thirty-second note | — | — | — | — |
| 1/64 Sixty-fourth note | — | — | — | — |
Hz = 1000 ÷ ms — the matching LFO / tremolo rate.
Pick one delay
- Delay time
- —
- Rate
- —
- Samples
- —
- Seconds
- —
Reverb pre-delay & decay
- Pre-delay
- —
- Decay / RT60
- —
- Total tail
- —
Decay = the chosen musical length minus the pre-delay, so the tail dies away just as the next beat or bar lands. Set the reverb’s decay (RT60) to that figure and its pre-delay to the first value.
How it works
One beat is a quarter note, so the length of a beat in milliseconds is
60000 ÷ BPM. Every other note value is a multiple of that: a whole note is four
beats, a half note two, an eighth note half a beat, and so on — in general
ms = (60000 ÷ BPM) × (4 ÷ note denominator). A dot adds half the note’s value
again (×1.5) and a triplet squeezes three notes into the space of two
(×2⁄3). At 120 BPM a quarter note is 500 ms, an eighth is 250 ms and
the famous dotted-eighth delay is 375 ms.
The Hz column is simply 1000 ÷ ms — the same number expressed as a rate, which is
what you type into a tremolo, chorus or filter LFO that is not tempo-synced. The samples figure
converts the delay to sample-accurate units for your chosen sample rate
(samples = seconds × sample rate), handy for nudging audio in a DAW. For reverb,
the usual trick is a very short pre-delay (a 1/64 or 1/32 note) to keep transients clear, then a
decay time that ends the tail on the next beat or bar: decay = note length − pre-delay.
Everything is arithmetic done in your browser with plain JavaScript. No tempo you type is uploaded, no account is needed and there are no ads. Tap the tempo button four or more times if you only know the groove by ear.
Frequently asked questions
How do I calculate delay time from BPM?
One beat is a quarter note, so a beat lasts 60000 ÷ BPM milliseconds. Every other note value scales from there: ms = (60000 ÷ BPM) × (4 ÷ note denominator). A dot adds half the note's length again (×1.5) and a triplet fits three notes into the space of two (×2⁄3). At 120 BPM that gives 500 ms for a quarter note, 250 ms for an eighth, 125 ms for a sixteenth, 375 ms for the classic dotted eighth and 166.67 ms for a triplet eighth. The chart on this page prints all of them at once for your tempo, so you can type the number straight into your delay plugin when it has no tempo-sync button.
What is the dotted eighth delay everyone talks about?
A dotted eighth note is an eighth note plus half its value again, so it lasts three sixteenths — 0.75 of a beat. At 120 BPM that is 375 ms, at 128 BPM 351.56 ms and at 90 BPM 500 ms. Because it lands off the grid against straight eighths, the repeats weave between the played notes instead of doubling them; it is the sound behind countless U2, EDM and pop guitar and synth parts. Pair it with a straight quarter-note delay on a second send and you get the classic two-tap pattern. Pick 1/8 plus Dotted in the "Pick one delay" section and the tool also shows the rate in hertz and the exact number of samples at your session's sample rate.
What pre-delay and decay time should I set on a reverb?
A short pre-delay keeps the dry transient clear before the reverb arrives — a 1/64 or 1/32 note is the usual starting point, which is 31.25 ms and 62.5 ms at 120 BPM. For the decay (RT60), the common trick is to let the tail die away exactly as the next beat or bar lands, so decay = the musical length you want minus the pre-delay. At 120 BPM a half-note tail with a 1/64 pre-delay means a 968.75 ms decay. These are musical starting points rather than rules: dense arrangements usually want shorter tails, sparse ballads longer ones. Everything here is calculated in your browser — nothing you type is uploaded, and there is no signup or ads.