Reverb Time Calculator
Pre-delay and decay ranges that sit with your tempo instead of smearing across it.
0 taps
Stability —
Beats per minute, 20 to 400.
Four beats of 4/4, pulsing at the tempo shown.
Every suggestion below is a fraction of this bar, so the tail ends on a musical boundary rather than across one.
- Per beat
- ms
- Per bar (4/4)
- ms
- Frequency
- Hz
- 1/8 delay
- ms
Reverb decay is a musical choice, not a formula, but tying it to note lengths keeps the tail clear of the next transient. At 120 BPM a 1/16 pre-delay is 125 ms and a half-note decay is 1,000 ms. The tool below shows both for room, plate and hall settings.
Settings by reverb type
Conventional starting points, not derived values. Adjust by ear from here.
| Type | Pre-delay | Decay range | Why |
|---|---|---|---|
| Room | 31.3 ms 1/64 | 250–500 ms 1/8–1/4 | Short and tight. Decay usually lands between an eighth and a quarter note. |
| Plate | 62.5 ms 1/32 | 500–1000 ms 1/4–1/2 | Dense and smooth. A quarter to half note decay keeps it clear of the next transient. |
| Hall | 125 ms 1/16 | 1000–2000 ms 1/2–1/1 | Long and wide. Half note to full bar, though at fast tempos this masks the groove. |
Note lengths to choose from
If none of the three presets fits, take any division below and use its length as a decay or pre-delay value.
| Note | Length | Typical use |
|---|---|---|
| Whole note 1/1 | ms | Long hall decay. Ambient and sparse arrangements only. |
| Half note 1/2 | ms | Standard hall or plate decay for mid-tempo material. |
| Quarter note 1/4 | ms | Plate decay. Common on snares and vocals. |
| Eighth note 1/8 | ms | Room decay. Adds space without blurring the groove. |
| Sixteenth 1/16 | ms | Long pre-delay, or a very short room on percussion. |
| Thirty-second 1/32 | ms | Pre-delay for plates. Keeps the source distinct. |
| Sixty-fourth 1/64 | ms | Short pre-delay. Barely audible as a gap. |
Why there is no single formula
Delay times are arithmetic. Reverb decay is not. How long a tail should last depends on arrangement density, the character of the source, and what the reverb is doing musically — none of which a calculator can know.
What is calculable is how long each note division lasts at your tempo. Tying decay to one of those lengths gives the tail a musical boundary to end on, which is why this tool gives ranges rather than a single number pretending to be an answer.
Fast tempos need shorter tails
At 174 BPM a bar lasts 1379 ms, so a decay of 2000 ms — a comfortable full bar at 120 BPM — would run nearly a bar and a half and smear across the groove. This is why drum and bass uses short, bright reverbs and ambient music can sustain tails of several seconds.
High-pass the return. Low-frequency energy in a tail accumulates faster than anything else. Rolling off below roughly 200–300 Hz lets you use a longer decay than would otherwise work.
Need every value at once?
The main BPM calculator shows milliseconds, delay times, reverb ranges, hertz and bar length together, updating from a single tempo.
Understand the maths
Pre-delay is the gap between the dry sound and the start of the reverb; decay is how long the tail takes to fall away. Tying decay to a note length keeps the tail from smearing into the next transient. There is no universal formula, which is why the tool gives ranges, not a single number.
Common questions
How do I set reverb decay to tempo?
Match the decay to a note length at your tempo so the tail falls away before the next transient. At 120 BPM a half-note decay is 1,000 ms. This is a starting point, not a rule.
What pre-delay should I use?
Short values, typically a 1/64 to 1/16 note. At 120 BPM that is roughly 31 to 125 ms. Longer pre-delay separates the dry signal from the tail and keeps vocals intelligible.
Is there a correct formula for reverb time?
No. Reverb decay is a musical decision that depends on arrangement density and the character of the source. What is calculable is how long each note division lasts at your tempo, which is what this tool provides.
Related tools and guides
- Delay Time Calculator Tempo-synced delay times in milliseconds for every note division, including dotted and triplet values, with notes on what each one does. Tool
- BPM to Milliseconds Converter Convert any tempo to milliseconds per beat and back again. Covers every note division from whole notes to 1/64, straight, dotted and triplet. Converter
- BPM Calculator Tap a tempo and get every value it drives: milliseconds per beat, delay and reverb times, hertz, frames and bar length. Free, instant, no sign-up.
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