The BPM to Milliseconds Formula
Milliseconds per beat equals 60,000 divided by BPM, because there are 60,000 milliseconds in a minute and BPM counts beats in that minute. Every other note value scales from there: halve it for an eighth note, multiply by 1.5 for dotted, by two thirds for triplet.
Where the number 60,000 comes from
milliseconds per beat = 60000 ÷ BPM
A minute is 60 seconds. A second is 1,000 milliseconds. So a minute is 60,000 milliseconds. BPM tells you how many beats are packed into that minute, so dividing the total by the count gives the length of one beat. There is nothing more to it than that.
This is a definition, not an approximation. At 120 BPM a beat is exactly 500 ms. At 128 BPM it is exactly 468.75 ms. Any rounding you see on this site is display formatting, not a limit of the calculation.
Scaling to other note values
A BPM beat is conventionally a quarter note. Everything else scales from it by a simple multiplier:
| Note | Multiplier | At 120 BPM |
|---|---|---|
| Whole note (1/1) | × 4 | 2000 ms |
| Half note (1/2) | × 2 | 1000 ms |
| Quarter note (1/4) | × 1 | 500 ms |
| Eighth note (1/8) | × 0.5 | 250 ms |
| Sixteenth (1/16) | × 0.25 | 125 ms |
| Thirty-second (1/32) | × 0.125 | 62.5 ms |
Dotted and triplet values
A dot adds half the note's value again, so a dotted note is 1.5 times the straight one. A triplet fits three notes into the space of two, so each is two thirds of the straight value.
dotted = straight × 1.5
triplet = straight × 2 ÷ 3
A useful check: three eighth-note triplets should add up to exactly one quarter note. At 120 BPM that is 166.6667 ms × 3 = 500 ms, which is the quarter note exactly. If your arithmetic does not close like this, the multiplier is wrong.
Worked example at 128 BPM
128 BPM is the house and techno default, so it is worth knowing by heart.
60000 ÷ 128 = 468.75 ms per beat
| Note | Straight | Dotted | Triplet |
|---|---|---|---|
| Whole note (1/1) | 1875 | 2812.5 | 1250 |
| Half note (1/2) | 937.5 | 1406.25 | 625 |
| Quarter note (1/4) | 468.75 | 703.13 | 312.5 |
| Eighth note (1/8) | 234.38 | 351.56 | 156.25 |
| Sixteenth (1/16) | 117.19 | 175.78 | 78.13 |
| Thirty-second (1/32) | 58.59 | 87.89 | 39.06 |
| Sixty-fourth (1/64) | 29.3 | 43.95 | 19.53 |
All values in milliseconds.
Going the other way
The formula inverts cleanly, because it is a straight reciprocal relationship:
BPM = 60000 ÷ milliseconds per beat
A 400 ms beat is 150 BPM. A 500 ms beat is 120 BPM. This is useful when you have a delay time you like on a piece of hardware and want to know what tempo it corresponds to.
Bars, not just beats. Multiply the beat length by the number of beats in a bar. In 4/4 at 128 BPM that is 468.75 × 4 = 1875 ms. In 3/4 it is three beats, giving 1406.25 ms.
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.
Use the tool
Convert any tempo to milliseconds per beat and back again. Covers every note division from whole notes to 1/64, straight, dotted and triplet.
Related tools and guides
- 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
- Methodology Every calculation on this site, written out with its derivation, rounding behaviour and known limitations. Nothing hidden behind the UI.
- 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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