81 BPM
81 beats per minute is one beat every 740.74 ms. Below: bar and phrase lengths, delay and reverb times, LFO rates, the genres that use this tempo, and the pitch change needed to mix in from nearby tempos. Start the metronome or tap along to a track to check it is really 81.
Updated 2026-10-17
81 BPM
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Beat, bar and phrase lengths at 81 BPM
At 81 BPM one beat lasts 740.74 ms and a 4/4 bar lasts 2.963 s. The beat is not a whole number of milliseconds, so round to the nearest 0.1 ms when you type times in by hand, or use your plugin's tempo sync. That is 1.35 beats per second, or 20.25 bars of 4/4 per minute.
Dance tracks are usually arranged in 8-, 16- and 32-bar phrases. At 81 BPM a 16-bar phrase takes 47.41 s and a 32-bar intro or outro takes 1:34.8 min. That is 15.41 s longer than the same 16 bars at 120 BPM. A six-minute track at this tempo contains about 122 bars.
| Length | Time | Milliseconds |
|---|---|---|
| 1 beat | 0.741 s | 740.74 ms |
| 1 bar (4 beats) | 2.963 s | 2962.96 ms |
| 4 bars | 11.85 s | 11851.85 ms |
| 8 bars | 23.7 s | 23703.7 ms |
| 16 bars | 47.41 s | 47407.41 ms |
| 32 bars | 1:34.8 min | 94814.81 ms |
| 64 bars | 3:09.6 min | 189629.63 ms |
Delay times at 81 BPM
Straight values follow the beat; dotted values are 1.5 times as long and triplets are two-thirds as long. At 81 BPM the popular dotted-eighth delay is 555.56 ms and a quarter-note slapback is 740.74 ms. The Hz column is the matching rate for an LFO, tremolo or auto-pan synced to the straight note.
| Note | Straight | Dotted | Triplet | Rate (straight) |
|---|---|---|---|---|
| 1/1 (one 4/4 bar) | 2962.96 ms | 4444.44 ms | 1975.31 ms | 0.337 Hz |
| 1/2 | 1481.48 ms | 2222.22 ms | 987.65 ms | 0.675 Hz |
| 1/4 (one beat) | 740.74 ms | 1111.11 ms | 493.83 ms | 1.35 Hz |
| 1/8 | 370.37 ms | 555.56 ms | 246.91 ms | 2.7 Hz |
| 1/16 | 185.19 ms | 277.78 ms | 123.46 ms | 5.4 Hz |
| 1/32 | 92.59 ms | 138.89 ms | 61.73 ms | 10.8 Hz |
Reverb times at 81 BPM
A common way to keep a reverb in time is to tie its pre-delay to a short note value and let the tail fade within a longer one. At 81 BPM a 1/64-note pre-delay is 46.3 ms and a 1/32-note pre-delay is 92.59 ms.
The decay control on most reverbs is RT60, the time it takes the tail to fall by 60 dB, so the audible tail ends earlier than the number shown. Treat these values as starting points and adjust by ear.
| Reverb character | Pre-delay | Decay (RT60) |
|---|---|---|
| Tight room on drums | 46.3 ms | 740.74 ms |
| Medium plate on vocals | 92.59 ms | 1481.48 ms |
| Large hall or pad wash | 92.59 ms | 2962.96 ms |
| Ambient tail over two bars | 185.19 ms | 5925.93 ms |
Genres at 81 BPM
81 BPM is a relaxed, mid-slow tempo. It sits in the middle of the ambient/downtempo range (60–100), in the middle of the hip-hop range (70–100) and in the middle of the reggae/dub range (70–100).
Counted at double-time (162 BPM) it matches footwork/juke, drum and bass and hardcore/gabber. A detector or a tag in your library may report either reading, so check by ear which one the drums suggest.
These ranges are common practice rather than rules: genre is decided by rhythm, sound and scene as much as by tempo, and plenty of tracks sit outside the usual numbers.
- Ambient/downtempo: typically 60–100 BPM — beatless ambient may not have a useful BPM at all.
- Hip-hop: typically 70–100 BPM — boom-bap often sits around 85–95.
- Reggae/dub: typically 70–100 BPM — the off-beat skank can make the pulse feel faster than it is.
Mixing into 81 BPM
To bring a track at another tempo up or down to 81 BPM, move its pitch fader by the percentage below. Without key lock the key moves too, by the number of semitones shown; about 6 % is one semitone, so changes beyond that are where key lock (master tempo) starts to matter.
A ±8 % pitch fader on a track at 81 BPM reaches 74.5–87.5 BPM; a ±16 % range reaches 68–94 BPM.
| Track tempo | Pitch change to reach 81 | Key shift without key lock |
|---|---|---|
| 75 BPM | +8 % | +1.33 st |
| 77 BPM | +5.19 % | +0.88 st |
| 79 BPM | +2.53 % | +0.43 st |
| 80 BPM | +1.25 % | +0.22 st |
| 82 BPM | −1.22 % | −0.21 st |
| 83 BPM | −2.41 % | −0.42 st |
| 85 BPM | −4.71 % | −0.83 st |
| 87 BPM | −6.9 % | −1.24 st |
Half-time, double-time and nearby tempos
Half-time of 81 BPM is 40.5 BPM and double-time is 162 BPM.
40.5 BPM is outside the 60–200 range of these pages; the half/double-time converter works with any value.
Each 1 BPM step at this tempo changes the beat by about 9.03 ms, so neighbouring tempos are close enough to beatmatch with a small pitch move.
Frequently asked questions
- How many milliseconds is one beat at 81 BPM?
- One beat (a quarter note) at 81 BPM is 60,000 ÷ 81 = 740.74 ms. A 4/4 bar is four beats, 2962.96 ms.
- What is the dotted eighth delay time at 81 BPM?
- A dotted 1/8 delay at 81 BPM is 555.56 ms: an eighth note (370.37 ms) multiplied by 1.5. A straight quarter-note delay is 740.74 ms and a quarter-note triplet is 493.83 ms.
- What genre is 81 BPM?
- Ambient/downtempo, hip-hop and reggae/dub commonly use 81 BPM. Genre ranges overlap, so the drum pattern and sound decide the style more than the number does.
- What is 81 BPM in Hz?
- 81 BPM is 1.35 Hz when one cycle equals one beat. An LFO synced to one bar runs at 0.3375 Hz, and one synced to sixteenth notes at 5.4 Hz.