Delay & Reverb Time Calculator

How do I use the delay calculator?

Set your tempo, read the milliseconds for the note you want, and paste them into your delay. In a bit more detail:

1. Set the tempo. Type the BPM of your song, nudge it with the plus and minus buttons, or tap along with the beat on the Tap button (or the T key).
2. Pick a note value. Find the note value you want in the table: straight, dotted or triplet. The highlighted row is one beat. Click any value to copy it.
3. Dial it into your delay. Paste the milliseconds into your delay’s time setting. For tremolo, auto-pan or a filter wobble, use the Hz value as the LFO rate instead.
4. Set the reverb. Choose a space in the reverb table and copy its pre-delay and decay. Then adjust by ear until the tail stops just before the next phrase.
5. Hear it. Press “Hear it” to play a short loop at your tempo through a delay set to your chosen note value, so you can hear how the echoes sit before you commit.

How do you convert BPM to milliseconds?

Divide 60,000 by the BPM. There are 60,000 milliseconds in a minute, and BPM is beats per minute, so 60,000 ÷ BPM is the length of one beat. In most music one beat is a quarter note.

1/4 note (ms) = 60000 / BPM
note (ms)     = 60000 / BPM × 4 × note value
dotted        = × 1.5
triplet       = × 2/3
rate (Hz)     = 1000 / ms

So at 120 BPM: a whole note is 60,000 ÷ 120 × 4 = 2,000 ms, a half note is 1,000 ms, a quarter is 500 ms, an eighth is 250 ms. A dotted eighth is 250 × 1.5 = 375 ms, and an eighth-note triplet is 250 × ⅔ = 166.67 ms.

What are the delay times for common tempos?

Here are the numbers people ask for most, worked out with the formula above. For any other tempo (or for triplets, LFO rates and reverb), use the calculator.

What’s the difference between straight, dotted and triplet delays?

A dotted note is 1.5 times as long as the straight note; a triplet is two thirds as long. They change where the echoes fall against the beat, which changes the whole feel.

• Straight echoes land on the grid. A 1/4 delay repeats on every beat: tidy, and easy to bury in the mix. A 1/8 is busier.
• Dotted echoes land between the beats, so they fill gaps rather than stacking on top of what you played. Dotted eighths are the classic guitar delay.
• Triplet echoes roll and swing. Lovely on a vocal tail or a slow ballad, and the secret ingredient in a lot of reggae and dub.

Why does a dotted-eighth delay sound so good?

Because the echoes land on the sixteenth notes you didn’t play. Play steady eighth notes into a dotted-eighth delay (three sixteenths long) and every repeat falls exactly halfway between two of your notes. Your eighths plus the echoes become a cascade of sixteenths, so a simple part sounds twice as busy and wonderfully hypnotic.

That’s the trick behind The Edge’s guitar sound with U2, most famously the intro to “Where the Streets Have No Name”. Try it: press Hear it above with “1/8 dotted” and “Eighth notes”. Then switch to “1/8” and hear how the magic disappears, because the echoes now land right on top of the notes. I spent an embarrassing evening trying this on my Cort with a cheap pedal set by ear. With the right number it took one minute.

How should I set reverb pre-delay to keep vocals clear?

Give the reverb a short, tempo-related pre-delay, so each word arrives dry before the reverb blooms behind it. Pre-delay is the gap between the dry sound and the start of the reverb. With none, the reverb smears straight over the consonants and the vocal sinks back into the mix. With 20–80 ms, the voice stays upfront and the space still sounds big.

• Start at a 1/64 note (31.25 ms at 120 BPM) for most vocals; a 1/128 for tight, small rooms.
• Going above about 100 ms starts to sound like a separate slapback echo. That can be a lovely effect, but it’s a choice.
• Set decay so pre-delay + decay fit the music: the tail should fade just before the next phrase or the next snare hit. The table above gives tempo-locked starting points.
• Mixing Suno or AI vocals? They often arrive with reverb baked in. Add less than you think, and high-pass the reverb return around 200–300 Hz so it doesn’t muddy the low end.

How do I convert milliseconds back to BPM?

Divide 60,000 by the milliseconds, if that time is one beat. A 500 ms echo is 120 BPM as a quarter note. But a 375 ms echo could be a quarter note at 160 BPM, an eighth at 80 BPM or a dotted eighth at 120 BPM: the ms → BPM box shows every option. It’s handy when you’ve found a delay time you love by ear and want to build a song around it, or when you’re trying to work out what someone else used.

What do the Hz values mean?

They are the note lengths written as rates, for anything with an LFO. Tremolo, auto-pan, chorus, phasers and filter wobbles all wobble at a rate in hertz. Rate = 1000 ÷ ms, so a quarter note at 120 BPM is 2 Hz (two wobbles a second) and a sixteenth is 8 Hz. Set a tremolo to a 1/8 or 1/16 rate and it locks to the groove instead of drifting against it.

Why I built this

I'm a guitarist: a Cort, a lot of enthusiasm, roughly twelve notes. Delay is how I make twelve notes sound like forty. For years I set my delay pedal by turning the knob until it “felt about right”, which meant every song had echoes that were slightly, maddeningly, out of time. I’d hear it on the recording, never in the room.

So here is the cheat sheet I wanted taped to my pedalboard: one tempo, every note value, every variant, click to copy. I added tap tempo because half the time I don’t know the BPM of the Suno track I’m playing over, and the “Hear it” button because a number in milliseconds means nothing to my ears until I hear the echoes dance.

Using tempo and delay in a Suno prompt

Suno doesn’t give you a delay knob, but it does listen to a BPM in the style box and to the names of effects. “Dotted-eighth delay guitar” and “plate reverb on vocals” are well-known production phrases, so they steer the sound much better than “spacey”. This snippet uses your BPM from the calculator:

Anthemic indie rock, 120 BPM, chiming electric guitar with dotted-eighth delay, driving bass, steady live drums, plate reverb on vocals, uplifting, euphoric, wide

Open in Prompt Studio →

Not sure what tempo to ask for? My guide to the best BPM for Suno by genre has a starting tempo for every style. Got the song back and want to know its real tempo? The BPM and key finder reads it from the audio; drop that number in here. You can also lay down your own groove at any tempo with the drum machine, or practise against a metronome.

How it works, and what it does with your data

The numbers are plain arithmetic from the formula above, recalculated as you type and rounded to two decimal places. Tap tempo averages the gaps between your last eight taps. The “Hear it” loop is built with the Web Audio API in your browser: a short plucked blip feeds a DelayNode with a feedback loop and a gentle low-pass filter on the repeats, scheduled slightly ahead so the timing is sample-accurate. The volume is capped well below full scale.

Nothing is uploaded and there’s no account. Your last BPM is saved in your browser’s local storage, on your device only. Want to try your delay and reverb on a real track? The music editor and the slowed + reverb maker both run in the browser, and the LUFS meter checks the loudness when you’re done.

Delay and reverb calculator FAQ