Compressor Time Calculator
Enter your song's tempo and get the note lengths in milliseconds — the rhythmic starting points for compressor attack and release. Based on Bobby Owsinski's tempo-synced approach.
| Note value | Straight (ms) | Dotted (ms) | Triplet (ms) |
|---|
Dotted values are 1.5× the straight length; triplet values are two-thirds of it. Use them as alternate release times when a straight subdivision feels a touch too fast or too slow against the groove.
Why sync compression to the tempo
A compressor is a rhythmic device whether you plan for it or not. Every time it clamps down and lets go, it moves the level of the track — and if that movement lines up with the beat, the compression feels like part of the groove instead of a random wobble. Mixing engineer and author Bobby Owsinski popularized the simple trick behind this page: convert the song's tempo into milliseconds and use those note lengths as your starting points for attack and, especially, release.
The math is just one line. A single beat — a quarter note — lasts 60000 ÷ BPM milliseconds. At 120 BPM that's 500 ms. Halve it as you go smaller: an eighth note is 250 ms, a sixteenth 125 ms, a thirty-second 62.5 ms. Set the compressor's release so the gain has recovered by roughly the next beat or subdivision, and every pump lands in time.
Attack vs. release — how to use these numbers
Release: sync it
Release is the setting that gains the most from tempo. Start on the eighth- or sixteenth-note value and let the compressor recover in time with the beat. On a bus or a whole mix, a quarter-note release breathes; on a busy rhythm part, reach for the shorter subdivisions.
Attack: shape the transient
Attack is chosen mostly by how much punch you want to let through — slower attacks keep transients snappy, faster ones tame them. The 1/16 and 1/32 values here make good reference points for those short attack times without reaching for a random number.
Then trust your ear
These are starting points, not commandments. Dial in the note value, watch the gain-reduction meter move in time with the song, then nudge until it feels right. If a straight subdivision pumps oddly, try the dotted or triplet value instead.
Frequently asked questions
How do you calculate compressor release time from BPM?
One beat (a quarter note) lasts 60000 ÷ BPM milliseconds. At 120 BPM that's 500 ms. Halve it for each smaller subdivision: an eighth note is 250 ms, a sixteenth 125 ms, a thirty-second 62.5 ms. Pick the subdivision that lets the compressor recover roughly by the next beat so its movement locks to the groove.
What is rhythmic or tempo-synced compression?
Choosing attack and release times that are musical subdivisions of the tempo instead of arbitrary numbers. When the compressor releases in time with the beat, its gain movement breathes with the song and pumps in a way that feels intentional. The idea is widely associated with mixing engineer and author Bobby Owsinski.
Should I set attack and release to these exact values?
Treat them as starting points, not rules. Note-length values give you a musically sensible place to begin, then you adjust by ear while watching the gain-reduction meter. Release benefits most from being tempo-synced; attack is usually chosen by how much transient you want to let through, with the shorter subdivisions as handy reference points.
Is the compressor time calculator free?
Yes. It's completely free with no sign-up and runs entirely in your browser. Nothing is uploaded — you just type a BPM and read the millisecond values.
A tip of the hat to Bobby Owsinski
This calculator exists because of the tempo-to-milliseconds technique that mixing engineer, producer, and author Bobby Owsinski has taught for years — most famously in The Mixing Engineer's Handbook. If you want the full reasoning and a stack of other practical mixing moves, his books are well worth owning. We're just doing the arithmetic for you.