Reverb & Delay Time Calculator
Calculate tempo-synced delay times in milliseconds from the song's BPM and a note value. Essential for producers and engineers locking effects to the groove of a track.
Last updated: September 2026
Formula below · 2 sources (aes.org, Wikipedia) · Updated Sep 2026
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About this calculator
Syncing delay and reverb to tempo ensures effects feel rhythmically cohesive rather than cluttered. The delay time for a given note value is: delay_ms = (240,000 / BPM) × noteValue, where 240,000 / BPM is the length of a whole note (four quarter-note beats) in milliseconds and noteValue is the fraction of a whole note (0.25 = quarter, 0.125 = eighth, 0.1875 = dotted eighth, 0.375 = dotted quarter). Feedback and room size shape how long the echoes and reverb tail last, but they do not change the time between repeats, so they do not change the delay time shown. A dotted eighth note delay at 120 BPM gives 2,000 × 0.1875 = 375 ms — a classic rhythmic effect used across pop, rock, and electronic music. Matching reverb pre-delay to tempo keeps transients clear while the tail fills the space musically.
How to use
Track tempo = 120 BPM, note value = Eighth Note (0.125), feedback = 30%, room size = Medium. Step 1: Whole note = 240,000 / 120 = 2,000 ms. Step 2: Delay = 2,000 × 0.125 = 250 ms. Set your delay plug-in to 250 ms — or use the tempo-sync option and select a straight eighth note — for a rhythmically locked echo that sits cleanly in the mix. At 30% feedback each repeat is 30% of the previous level, so the echoes fall below −60 dB after about six repeats (1.5 s).
Frequently asked questions
What delay time should I use for a dotted eighth note at 120 BPM?
At 120 BPM, one quarter note lasts 500 ms. A dotted eighth note is 1.5 times an eighth note, and an eighth note is half a quarter note (250 ms), so a dotted eighth = 250 × 1.5 = 375 ms. This delay time is one of the most popular in modern production because it creates a syncopated, cascading echo that fills rhythmic gaps without clashing with downbeats. The U2 guitarist The Edge famously popularised this technique in the 1980s, and it remains a staple in pop, indie, and electronic music production.
How does delay feedback percentage affect the number of audible repeats?
Feedback controls how much of the delayed signal is fed back into the delay input, determining how long echoes continue. At 0% feedback there is only one repeat; at 50% each repeat is half the level of the previous, giving roughly 3–5 audible echoes before fading below perception. At 90% feedback, echoes sustain much longer and can build into a washy, ambient texture. Feedback above 99% can cause runaway self-oscillation — an intentional effect in some electronic music but destructive to a mix if uncontrolled. For clean, rhythmic delay effects in a mix, 20–40% feedback is a common starting range.
Why is it important to sync reverb pre-delay time to the song's BPM?
Pre-delay is the gap between the dry signal and the onset of the reverb tail. Setting it to a musically related time — typically an eighth or sixteenth note at the track's BPM — preserves the clarity and attack of the source instrument before the reverb washes in, preventing the mix from sounding muddy or undefined. For example, at 120 BPM, a 125 ms pre-delay (one sixteenth note) lets the vocal transient cut through cleanly before the reverb tail envelops it. This technique is especially important for lead vocals, snare drums, and any element that needs presence and intelligibility in a dense arrangement.