What this calculator does
The duration in music of any note value depends entirely on tempo. This calculator converts a note value, from a whole note down to a sixteenth, dotted notes and eighth-note triplets, into an exact duration in seconds and milliseconds once you set the tempo in beats per minute.
The starting point is the quarter note, which by convention lasts exactly one beat: at 120 BPM that is 60 divided by 120, or half a second. Every other note value is a simple fraction or multiple of that same figure, which is why a producer or DJ can line up a delay or a sample cut to the beat just from the tempo and a note-value chart.
The formula
Divide 60 by the tempo in beats per minute to get the duration of one quarter note in seconds, then multiply by the note-value multiplier: 4 for a whole note, 2 for a half, 1 for a quarter, 0.5 for an eighth, 0.25 for a sixteenth, 1.5 times the plain value for a dotted note, and two-thirds of the plain value for a triplet.
| Term | Meaning |
|---|---|
| BPM | Beats per minute, the tempo the note duration is measured against. |
| Quarter note | The note value equal to one beat, lasting 60 divided by BPM seconds. |
| Dotted note | A note extended by half its own value again, so a dotted quarter lasts one and a half quarter notes. |
The inputs explained
| Field | What to enter |
|---|---|
| Tempo (BPM) | The tempo in beats per minute. |
| Note value | The note value to convert into a duration. |
When to use it
Setting a delay effect to the beat
Audio delay and reverb plugins are often set in milliseconds, so converting a note value such as a dotted eighth at the track tempo gives the exact millisecond figure to enter for a delay that stays in time.
Working out how a piece of music will feel at a new tempo
Rehearsal or practice at a slower tempo makes every note value proportionally longer, and this calculator shows exactly how much longer for any given note.
Programming a drum machine or sequencer by hand
Step sequencers often need a step length in milliseconds rather than a musical note name, and this converts one into the other for any tempo.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How note duration in seconds changes with tempo, for a quarter note
The quarter note duration, in seconds, across a range of common tempos.
| Tempo | Duration in seconds | Duration in milliseconds |
|---|---|---|
| 60 BPM | 1.000 s | 1,000 ms |
| 90 BPM | 0.667 s | 667 ms |
| 120 BPM | 0.500 s | 500 ms |
| 140 BPM | 0.429 s | 429 ms |
| 160 BPM | 0.375 s | 375 ms |
| 180 BPM | 0.333 s | 333 ms |
How duration differs across note values at a fixed tempo
A fixed tempo of 120 BPM, across the available note values.
| Note value | Duration in seconds | Duration in milliseconds |
|---|---|---|
| Whole | 2.000 s | 2,000 ms |
| Half | 1.000 s | 1,000 ms |
| Quarter | 0.500 s | 500 ms |
| Eighth | 0.250 s | 250 ms |
| Sixteenth | 0.125 s | 125 ms |
Questions
How long is a quarter note at 120 BPM?
Exactly half a second. The quarter note is defined as one beat, so at 120 beats per minute each beat, and each quarter note, lasts 60 divided by 120, which is 0.5 seconds.
What is the duration in music of a dotted note?
A dot adds half the note's own value again, so a dotted note lasts one and a half times as long as the plain note. A dotted quarter note at 120 BPM lasts 0.75 seconds, one and a half times the 0.5 second plain quarter note.
How does a triplet duration work?
A triplet fits three notes into the time normally taken by two of the same value, so each triplet note lasts two-thirds of the plain note's duration. An eighth-note triplet is two-thirds the length of a plain eighth note.
Why does this matter outside of playing an instrument?
Producers and sound designers use exact note-to-millisecond conversions to set delay, echo and gate effects so they land precisely on the beat, rather than sounding slightly out of time with the track.
For working with tempo and beat counts more generally, see the angular frequency calculator for the equivalent idea in physics, where a repeating cycle is also converted between a rate and a period.