BPM to MSStraight, dotted, and triplet timing in milliseconds
Understand the multipliers behind note divisions, compare timings at 120 BPM, and handle swing and non-quarter-note tempo markings correctly.
For the same note division, a dotted note lasts 1.5 times the straight value. A triplet note lasts two thirds of the straight value. At 120 BPM, that makes an eighth note 250 ms, a dotted eighth 375 ms, and an eighth-note triplet about 166.667 ms.
The note name matters. An eighth-note triplet and a quarter-note triplet are different durations, even though both use the same two-thirds multiplier.
Begin with a quarter-note beat
The calculator treats BPM as quarter-note beats per minute. Its starting point is 60,000 / BPM milliseconds. A whole note is four of those beats, a half note is two, an eighth note is half a beat, and a sixteenth is a quarter of a beat.
In a 4/4 passage, a whole note fills one bar. That relationship changes with the time signature: a bar of 3/4 holds three quarter-note beats, not four. Changing the time signature alone does not change a quarter note’s duration when the quarter-note BPM stays the same.
A dot adds half the original length
To get a dotted note, add half of its straight duration. At 120 BPM, a quarter is 500 ms; half of that is 250 ms, so a dotted quarter is 750 ms.
A dotted eighth uses the eighth note as its starting point: 250 + 125 = 375 ms. The extra length is why dotted-eighth delay repeats land at intervals of three sixteenth notes. A dot does not mean an extra beat, and it does not mean the same added number of milliseconds for every note division.
A triplet fits three notes into the space of two
Three eighth-note triplets occupy the duration of two ordinary eighth notes. At 120 BPM, those two ordinary eighths total 500 ms. Dividing by three gives approximately 166.667 ms per eighth-note triplet.
Quarter-note triplets instead occupy two ordinary quarter notes. At the same tempo, their individual duration is approximately 333.333 ms. You can calculate either by multiplying the corresponding straight value by 2 / 3.
| Note at 120 BPM | Straight | Dotted | Triplet |
|---|---|---|---|
| Quarter (1/4) | 500.000 ms | 750.000 ms | 333.333 ms |
| Eighth (1/8) | 250.000 ms | 375.000 ms | 166.667 ms |
| Sixteenth (1/16) | 125.000 ms | 187.500 ms | 83.333 ms |
In the compact reference table, 1/8T means an eighth-note triplet. The main grid presents the triplet value in a separate column for every supported note row.
Triplets are not a universal swing setting
A strict triplet grid divides the beat into three equal parts. Swing usually shifts the timing of alternating subdivisions, and a DAW’s swing control may use a range of ratios or its own groove model. A shuffled phrase can therefore sound different from a sequence of equally spaced triplet notes.
When matching an existing performance, use the calculated value as a reference and check the recorded attacks. Do not expect a triplet delay setting to reproduce every swung rhythm automatically.
Check what the tempo marking counts
Some scores count a dotted quarter as the beat, particularly in compound meter. A marking of dotted-quarter = 120 means that dotted quarter lasts 500 ms. Because a dotted quarter contains 1.5 quarter notes, the equivalent quarter-note tempo is 180 BPM.
For that example, enter 180 in this calculator and read the Dotted column of the quarter-note row to get 500 ms. This conversion is only needed when the stated beat unit differs from the calculator’s quarter-note assumption; many DAWs already report tempo in quarter-note BPM.
Once the beat unit is clear, use the delay guide or reverb guide to turn those durations into practical parameter settings.