Reverb calculator and delay calculator: BPM to ms

Reverb calculator math is simple: a quarter note lasts 60000 ÷ BPM milliseconds, pre-delay is a small fraction of that beat (a 1/64 note is 31.25 ms at 120 BPM), and the decay runs until the tail lands on a musical boundary, usually a 1/2 note, 1 bar or 2 bars (1, 2 and 4 seconds at 120 BPM). Type your tempo above to get those numbers for every room size, or read them off the tables below. The same tool is a delay calculator: every note value in milliseconds and Hz, straight, dotted and triplet.

Call it a delay time calculator, a reverb time calculator, a pre-delay calculator or a BPM-to-ms chart: it turns your tempo into exact effect times for any DAW, plugin or guitar pedal. For the same beat in bars and minutes, use the song length calculator.

How to use it

1. Enter your BPM. Type it, drag the slider, hit a preset, or use the Tap button to find the tempo by ear. Your DAW shows the project tempo in the transport bar.
2. Grab your delay time. Pick a note value. Use Normal for straight timing, Dotted for a wide bounce, Triplet for a rolling feel. Copy the ms (or the Hz) into your delay.
3. Dial your reverb. Match the room size to your section, then use the pre-delay and decay it gives you. Bigger space, longer tail.

Pre-delay calculator table (BPM to ms)

Pre-delay is the gap between the dry signal and the first reflections. Our ears expect that gap, so a tempo-synced value keeps the reverb off the consonant or the drum hit while still feeling locked to the groove. 1/128 and 1/64 are the usual vocal and snare values, 1/32 suits big halls and slow songs, and 1/16 (125 ms at 120 BPM) is already slapback territory.

Formula: pre-delay (ms) = 240000 ÷ BPM ÷ note division. At 95 BPM a 1/128 note is 19.74 ms. Vocal-specific starting points are in vocal reverb settings.

Reverb time calculator table (decay by BPM)

Total reverb time is how long the tail takes to fall away (the RT60 on most plugins). Set it so the tail ends on a beat: a 1/2 note for drums and busy vocals, 1 bar for most lead vocals and pads, 2 bars for ballads and breakdowns, 4 bars only for ambient washes. Subtract the pre-delay from the total to get the decay setting, as the tool above does.

Which reverb type for which decay

Decay time is the first thing that separates reverb types, so once the table gives you a number you know what to reach for. Typical ranges, not rules.

Torn between a longer reverb and a delay on a vocal? Reverb vs delay on vocals walks through when each wins. For plugin picks by type, see best reverb plugins.

Delay calculator table (BPM to ms)

Ten common tempos, six note values. Straight 1/4 and 1/8 sit on the grid, dotted 1/8 lands between beats for a wide bounce, triplets roll. For any other tempo: 1/4 note (ms) = 60000 ÷ BPM, halve for each smaller value, × 1.5 for dotted, × 2/3 for triplet.

A slap delay on vocals usually sits under 150 ms, which at most tempos means the 1/16 column or shorter (slap delay on vocals). Throws want a 1/4 or dotted 1/8 so the repeat lands on a beat (vocal throw delay).

Delay times for depth and movement

Short, tempo-synced delays add depth you feel but barely hear. Longer ones add movement that becomes part of the arrangement. Try three delays at different note values panned left, center and right; dotted and triplet values are where it gets interesting. Guitar pedals that take a delay in milliseconds use the same numbers.

Tune your LFO and mod FX to the tempo

The Hz column is not just for delay. Drop those values into an LFO to get tremolo, vibrato, auto-pan or filter sweeps that lock to the beat instead of drifting against it. The full workflow for syncing every effect in a session is in how to make effects tempo-synced.

When the tempo moves, the times move

Everything here scales with BPM. Repitch a sample without time-stretch and its tempo shifts too, so re-run the numbers at the new tempo; the pitch & semitone calculator gives that BPM from the semitone shift. The same beat math sets compressor release times: see the compressor settings calculator.

Pro tips for tempo-synced reverb

Tune a room reverb to the snare so the tail dies just before the next hit. In 4/4 with the snare on 2 and 4, start from the 1/2-note total. Clean it up with a low cut and a high cut on the reverb return. For extra space without mud, sidechain the reverb to its source so it ducks while the part plays and blooms in the gaps. The numbers are a starting point, not a rulebook: use your ears, because the only thing that matters is that the track sounds good.

Delay & reverb calculator FAQ