Type your song’s tempo or tap it in, then press Calculate. Copy a delay time into your delay plugin when it isn’t synced to your DAW, or use the Hz value for tempo-synced LFOs, tremolo and auto-pan. For reverb, start with the suggested pre-delay and decay for the size of space you want, then adjust by ear. Everything runs in your browser.
Divide 60,000 by the BPM to get one quarter note in milliseconds. At 120 BPM a quarter note is 500 ms, an eighth note is 250 ms and a sixteenth is 125 ms. Halve the value for each smaller note.
A dotted note is 1.5 times the straight note, so a dotted eighth at 120 BPM is 375 ms. A triplet is two thirds of the straight note, so an eighth-note triplet at 120 BPM is about 166.7 ms.
Divide 1,000 by the time in milliseconds. A 500 ms quarter note at 120 BPM equals 2 Hz, which is the rate to use for an LFO, tremolo or auto-pan that should move once per beat.
Pre-delay is the gap before the reverb starts. Short values keep a sound close; longer ones let vocals and drums stay clear in front of the tail. The presets here sync it to a note value, from 1/128 for a small room up to 1/16 for a large hall, so it stays in time with the song.
Pick the note length the tail should fill, such as a quarter note for a small room or a full bar for a hall, and subtract the pre-delay. The calculator does this for you so the reverb dies away on the grid instead of smearing into the next hit.
The note values are the same in any time signature, because a quarter note at a given BPM is always the same length. Only the bar-based reverb suggestions assume four beats per bar.