# How do I calculate BPM?

Works out the tempo of a song in beats per minute from the beats counted in a time, or the time or beats from the tempo, and the length of each note value in milliseconds.

- Page: https://www.acalculator.org/everyday-life/bpm-calculator
- JSON spec: https://www.acalculator.org/everyday-life/bpm-calculator.json
- Version: 77a8235dc6cf

## Default answer

Example with the default inputs (Beats counted 32, Time 15 s): 32 beats in 15 s is 128 BPM.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| beats | Beats counted | How many beats you counted. |
| time | Time | How long you counted for. |
| bpm | Tempo (BPM) | The tempo in beats per minute, from 1 to 1,000. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| beats | Beats counted | How many beats you counted. |
| seconds | Time | How long you counted for. |
| bpm | Tempo | Beats per minute: beats × 60 ÷ seconds. |
| beat | Beat (quarter note) | The length of one beat, a quarter note: 60,000 ms ÷ BPM. |
| half | Half note | Two beats. |
| whole | Whole note (4/4 bar) | Four beats, one bar of 4/4. |
| eighth | Eighth note | Half a beat. |
| sixteenth | Sixteenth note | A quarter of a beat. |
| dottedEighth | Dotted eighth note | Three quarters of a beat. |
| tripletEighth | Eighth-note triplet | A third of a beat. |

## Method

BPM = beats × 60 ÷ seconds; one beat (a quarter note) lasts 60,000 ÷ BPM milliseconds

## Assumptions

- The beat is a quarter note, as in 4/4 time; half a beat is an eighth note.
- A dotted note is 1.5 times its plain length; a triplet eighth is a third of a beat.
- The tempo is steady over the time counted.

## Worked examples

1. beats = 32, time = 15 gives bpm = 128, beat = 0.46875, eighth = 0.234375, dottedEighth = 0.351563. Source: SI Brochure (BIPM, 9th edition, 2019), Table 8: 1 min = 60 s.
2. bpm = 120, time = 30 gives beats = 60, beat = 0.5, whole = 2, sixteenth = 0.125. Source: SI Brochure (BIPM, 9th edition, 2019), Table 8: 1 min = 60 s.
3. beats = 100, bpm = 90 gives time = 66.666667, tripletEighth = 0.222222.

## FAQ

### How do I calculate BPM?

Count the beats for a set time, then multiply by 60 and divide by the seconds. 32 beats in 15 seconds is 32 × 60 ÷ 15 = 128 BPM. Counting for longer, 30 seconds or a minute, gives a steadier answer.

### What is the quickest way to count?

Count the beats for 15 seconds and multiply by 4, or for 6 seconds and multiply by 10. The calculator does the same sum for any time you counted.

### How many milliseconds is one beat?

Divide 60,000 by the BPM. At 120 BPM a beat lasts 60,000 ÷ 120 = 500 ms, an eighth note 250 ms and a sixteenth note 125 ms. These are common delay times for a delay effect set in time with the song.

### What is a dotted eighth or a triplet?

A dotted note lasts one and a half times its plain length, so a dotted eighth is three quarters of a beat. An eighth-note triplet fits three notes in one beat, so each lasts a third of a beat.

### Does this work for music not in 4/4 time?

The page takes the beat as a quarter note, as in 4/4, 3/4 and 2/4 time. In 6/8 the felt beat is often a dotted quarter; count those beats and read the tempo as dotted quarters per minute.

### Can I find how many beats fit in a time?

Yes. Enter the tempo and the time, and leave the beats empty. At 120 BPM, 30 seconds hold 60 beats.

## Sources

- Bureau International des Poids et Mesures, The International System of Units (SI Brochure, 9th edition, 2019), Table 8: 1 min = 60 s.