TIMING GUIDE
First define a beat.
Then divide the time.
Beatdelay converts one constant musical tempo and a selected note value into a duration. The reference beat is explicit so a dotted-quarter tempo marking can be interpreted without silently treating it as a quarter-note marking.
Why 60,000 ÷ BPM?
A minute contains 60,000 milliseconds. If a chosen reference beat occurs B times per minute, one such beat lasts 60,000/B ms. A 120 BPM quarter-note reference therefore lasts 500 ms per quarter note.
The reference beat is a definition of the entered tempo. Selecting a half-note reference at the same 120 BPM means 120 half notes per minute; a quarter note then lasts 250 ms. Changing the reference selector deliberately changes that relationship. Changing only milliseconds/seconds display does not.
The note ratios
Use quarter-note units as a common musical measure: a whole note is 4, a half is 2, a quarter is 1, an eighth is 1/2, and a sixteenth is 1/4. For a note with denominator d, its straight duration is 4/d quarter-note units.
One dot multiplies a straight duration by exactly 3/2. An ordinary triplet multiplies it by exactly 2/3: three triplet notes occupy the duration of two straight notes with the same name. These are musical duration ratios; no time-signature, swing or performance pattern is guessed.
Reference beat duration = 60,000 ÷ BPM
Target quarter units = (4 ÷ note denominator) × treatment
Target reference beats = target quarter units ÷ reference quarter units
Target milliseconds = reference beat duration × target reference beats
Seconds = milliseconds ÷ 1000
Ideal repetition rate (Hz) = 1000 ÷ milliseconds
Worked timings at 120 quarter-note BPM
| Target | Reference beats | Duration |
|---|---|---|
| Whole note | 4 | 2000 ms |
| Quarter note | 1 | 500 ms |
| Straight eighth | 1/2 | 250 ms |
| Dotted eighth | 3/4 | 375 ms |
| Eighth-note triplet | 1/3 | 500/3 ms ≈ 166.666666667 ms |
| Sixteenth | 1/4 | 125 ms |
For the triplet eighth, the repetition rate is exactly 6 Hz because six intervals of 1/6 second fit into a second. That is a repetition rate; it does not describe the pitch of the audio being delayed.
Worked example: a dotted-quarter reference
At 60 dotted-quarter BPM, one dotted-quarter reference beat lasts 1000 ms and contains 3/2 quarter-note units. A straight quarter contains 1 unit, so it is 2/3 of the reference beat: exactly 2000/3 ms, approximately 666.666666667 ms. A dotted quarter is one full reference beat and remains 1000 ms.
A metre such as 6/8 does not by itself supply this calculator’s BPM reference. Select the beat named by your actual tempo marking or chosen musical convention.
Decimal tempos and repeating results
At 120.5 quarter-note BPM, a quarter note lasts exactly 120,000/241 ms. Beatdelay retains the entered decimal BPM as an exact rational value for its arithmetic. It does not truncate 120.5 to 120, round each intermediate note duration, or replace 2/3 by 0.667.
Visible outputs use rounded decimal values. Text and CSV include exact fractions alongside approximations rounded to at most 12 decimal places. The main ms/s display preference is recorded separately; it does not alter the exact result.
Manufacturer context
Ableton’s Live 11 Delay documentation describes tempo-related beat divisions and a millisecond time mode. It provides context for why this conversion is useful; Beatdelay does not operate the effect or reproduce its interface.
BOSS/Roland’s DM-101 reference relates tap divisions to a quarter-note reference and displays dotted/triplet note percentages. Some displayed percentages are rounded. Beatdelay uses exact note ratios rather than taking 67% as an exact substitute for 2/3. It does not predict a particular device’s accepted settings.
What the calculation covers
This is constant-tempo note-duration arithmetic. No microphone, audio file, sound playback or browser metronome is involved. It does not determine tempo from a recording or account for swing, tuplets other than ordinary triplets, tempo changes, human timing, DSP latency, feedback decay, reverb tails or equipment setting limits.
Supported BPM bounds are 0.000001–1,000,000. They are software limits rather than musical recommendations or hardware specifications. Number text is limited to 100 characters and decimal exponents to ±30. Blank, zero, negative or invalid active entries hide the previous result and disable exports.