How this instrument works
A quarter note at any given tempo lasts exactly 60000/bpm milliseconds — 60000 because there are 60,000 milliseconds in a minute, and bpm tells you how many quarter-note beats fit into that minute. Other note values are simple fractions or multiples of that quarter-note length: an eighth note is half as long, a dotted eighth is three-quarters as long, a half note is twice as long, and so on.
Producers and mix engineers use this arithmetic to set delay times and reverb pre-delay so that echoes and reflections land precisely on the beat (or a musically related subdivision of it) instead of at some arbitrary, unrelated millisecond value. A delay that isn't tempo-synced can sound like it's fighting the groove; one dialled to a clean note-value fraction of the tempo locks in and often disappears into the track in a musical way.
This instrument covers the delay-time subdivisions engineers reach for most often: quarter, eighth, dotted eighth, sixteenth, and half notes. Feed it the tempo and pick a subdivision, and it returns the millisecond figure directly — the same number you'd type into a delay pedal's time knob or a DAW plugin's manual-ms mode.
- Enter Tempo (beats per minute) — the song or session's bpm.
- Choose Note value / delay subdivision from the dropdown — quarter, eighth, dotted eighth, sixteenth, or half note.
- Read Delay / reverb time (milliseconds) directly beneath the inputs.
- Use the same millisecond figure for a delay pedal's time knob, a DAW delay plugin's ms field, or a reverb's pre-delay parameter.
- Tempo must be greater than zero for the instrument to return a time.
Worked example — quarter-note delay at 120 bpm
Enter bpm = 120 and choose Quarter note (1/4), a note-value factor of 1. That's (60000 / 120) x 1 = 500.0 ms. Delay / reverb time reads 500.0.
500 ms is a classic, clearly audible slap-back delay time at 120 bpm — long enough to hear as a distinct repeat rather than a blur, and precisely locked to the beat because it's exactly one quarter note long.
Questions
Why does the formula use 60000 instead of 60?
Because the result is in milliseconds, not seconds. There are 60,000 milliseconds in a minute, so 60000/bpm gives the length of one quarter-note beat directly in milliseconds — the unit delay pedals and DAW plugins expect, avoiding an extra step of converting seconds to milliseconds afterward.
What's a dotted eighth note delay, and why is it so common?
A dotted eighth is one and a half times an eighth note's length (0.75 of a quarter note), and setting a delay to that value creates a rhythmic, syncopated repeat pattern rather than a straight echo. It's the setting behind U2 guitarist The Edge's signature delay sound — at 100 bpm it works out to exactly 450 ms.
Can I use this for reverb pre-delay as well as echo/delay effects?
Yes. Pre-delay is the gap, in milliseconds, between the dry sound and when the reverb tail begins, and engineers often set it to a tempo-synced note value for the same reason they sync delay repeats — so the reverb's onset feels locked to the music rather than arbitrary. Any of this instrument's five note-value options works equally well for pre-delay.
Does this work with any delay pedal or plugin?
Yes, as long as the device or plugin has a manual millisecond time entry rather than only a built-in tempo-sync mode. If your gear already syncs to tempo and note division automatically, this calculator mainly helps you understand or double-check what time value it's landing on.
Which note value should I pick for a specific rhythmic feel?
Straight subdivisions (quarter, eighth, sixteenth) repeat directly on the beat grid and feel tight and rhythmic; a dotted eighth deliberately falls off the grid and creates a bouncing, syncopated pattern; a half note gives a slow, spacious echo. There's no single correct choice — it depends on the part and the genre.