The formula
One beat lasts 60,000 ÷ BPM milliseconds. A quarter note is one beat, an eighth half of that, a sixteenth a quarter. A dotted note is 1.5 times its plain length; a triplet is ⅔ of it, because three fit in the space of two.
Delay times at common tempos
| BPM | 1/4 | 1/8 | 1/16 | 1/8 dotted | 1/8 triplet | 1/16 dotted |
|---|---|---|---|---|---|---|
| 60 | 1,000.0 | 500.00 | 250.00 | 750.00 | 333.33 | 375.00 |
| 70 | 857.14 | 428.57 | 214.29 | 642.86 | 285.71 | 321.43 |
| 80 | 750.00 | 375.00 | 187.50 | 562.50 | 250.00 | 281.25 |
| 90 | 666.67 | 333.33 | 166.67 | 500.00 | 222.22 | 250.00 |
| 100 | 600.00 | 300.00 | 150.00 | 450.00 | 200.00 | 225.00 |
| 110 | 545.45 | 272.73 | 136.36 | 409.09 | 181.82 | 204.55 |
| 120 | 500.00 | 250.00 | 125.00 | 375.00 | 166.67 | 187.50 |
| 128 | 468.75 | 234.38 | 117.19 | 351.56 | 156.25 | 175.78 |
| 130 | 461.54 | 230.77 | 115.38 | 346.15 | 153.85 | 173.08 |
| 140 | 428.57 | 214.29 | 107.14 | 321.43 | 142.86 | 160.71 |
| 150 | 400.00 | 200.00 | 100.00 | 300.00 | 133.33 | 150.00 |
| 160 | 375.00 | 187.50 | 93.75 | 281.25 | 125.00 | 140.63 |
| 170 | 352.94 | 176.47 | 88.24 | 264.71 | 117.65 | 132.35 |
| 174 | 344.83 | 172.41 | 86.21 | 258.62 | 114.94 | 129.31 |
All values in milliseconds. At 120 BPM, for example, a beat is 500.00 ms. Need the same numbers as LFO or tremolo rates? See BPM to Hz. Keep time while you play with the metronome, or find a song’s tempo with tap tempo.
Frequently asked questions
How do you convert BPM to milliseconds?
Divide 60,000 by the tempo: that is one beat (a quarter note) in milliseconds. At 120 BPM a beat is 500 ms. Halve it for an eighth note, halve again for a sixteenth; multiply by 1.5 for a dotted note and by ⅔ for a triplet.
What is a dotted eighth delay?
A delay of three sixteenth notes — 1.5 times an eighth. At 120 BPM that is 375.00 ms. Its repeats fall between the beats, which is why it is the classic rhythmic guitar delay.
How do I set reverb pre-delay from the tempo?
A common starting point is a short note value — a 64th or a 32nd — so the reverb starts just after the dry sound, in time with the song. Set the decay so the tail ends around a quarter or a half note, so it clears before the next phrase.
Why are there sample counts?
Samplers, loop editors and some plug-ins ask for lengths in samples rather than milliseconds. The number depends on the session’s sample rate, so switch between 44.1 and 48 kHz to match yours.