How to Calculate Delay Time: Dotted-Eighth ms and a BPM Chart

The delay time formula is “60000 ÷ BPM”

Matching delay time to a song starts with the length of one quarter-note beat. A minute is 60000 milliseconds, so a quarter note lasts “60000 ÷ BPM” ms. At BPM 120 that’s 60000 ÷ 120 = 500 ms; at BPM 100 it’s 600 ms, and at BPM 150 it’s 400 ms.

For other note values, just multiply the quarter-note length. An eighth note is half, a sixteenth is a quarter, and a half note is double. A dotted note is 1.5 times the original, and a triplet is two-thirds of the original.

Delay time chart by BPM (ms)

Here are delay times for common BPMs, rounded to one decimal place. When entering them into hardware or plug-ins, truncating or rounding the decimals won’t make an audible difference.

For BPMs not in the chart, or for lengths like dotted quarters, quarter triplets and 32nd notes, enter the BPM into the BPM Tap Tempo & Delay Time Calculator: it lists straight, dotted and triplet values for every note from a whole note down to a 64th. If you don’t know the song’s BPM, you can measure it in the same tool by tapping along (tips are in how to find a song’s BPM).

Why dotted-eighth delay is so popular, and how to use it

The dotted eighth is the most widely used guitar delay setting. Put a dotted-eighth delay on a phrase played in eighth notes and the dry note and the repeat alternate, offset by a sixteenth, creating a busy sixteenth-note pattern you never actually played. That shimmering, cascading arpeggio sound, made famous by U2’s The Edge, works exactly this way.

1. 1

   Measure the song’s BPM

   For a song at BPM 120, the dotted eighth is 375 ms. A difference of just 1 BPM changes it by around 3 ms, so measure to a decimal place if you can.

2. 2

   Set the delay time to a dotted eighth

   Choose 1/8D (or ♪.) with the time knob or tempo sync. On gear that takes milliseconds, enter 375.

3. 3

   Raise the mix (effect level) to about the same as the dry signal

   When you’re using the repeats to create sixteenth notes, a quiet delay won’t produce the rhythm. Aim for roughly the same level as the dry signal, or slightly lower.

4. 4

   Keep feedback (repeats) to 1–3

   Too many repeats pile up and muddy the sound. Letting them die away after two or three keeps the rhythm clear.

5. 5

   Play in eighth notes

   If your picking lines up precisely on eighth notes, the dry signal and the delay fill the sixteenth-note gaps cleanly.

Choosing a note value for your delay

The note value you pick changes how the delay sounds a great deal. Here’s a guide by instrument and style.

When putting delay on vocals, common tricks to keep the words intelligible are a high-cut filter on the delay signal, or sidechaining so the delay ducks while the singer is singing. When combining it with reverb, matching the reverb’s pre-delay to the tempo too helps everything gel.

Matching gear that has no tempo sync or tap tempo

Older analog delays and knob-only compact pedals may not let you type in milliseconds. In that case, set it like this.

1. 1

   Set the knob near the calculated milliseconds

   If the manual gives the minimum and maximum delay times, you can estimate the value from the knob position. For example, if a delay maxes out at 600 ms and you want 300 ms, the knob goes roughly in the middle (some models don’t have an evenly spaced scale).

2. 2

   Fine-tune against a metronome

   Run a metronome at the song’s BPM, play quarters or eighths on the guitar with the delay on, and move the knob until the repeats stop drifting from the click.

3. 3

   Turn up the feedback to check

   Temporarily raising the feedback makes any drift build up with each repeat, so it’s easier to hear. Set it back once it lines up.

Common calculation mistakes and things to watch

• Measuring the BPM at double or half: if you measure a BPM 140 song as 70, what you think is a quarter note comes out the length of a half note (857.1 ms). For counting tempo, see telling double time from half time
• Mixing up dotted and triplet: a dotted note is 1.5 times longer, a triplet is two-thirds as long. At BPM 120 a dotted eighth is 375 ms and an eighth triplet is about 166.7 ms
• Using the dotted-quarter tempo for a song in 6/8: a score marking of “dotted quarter = 60” is BPM 90 in a DAW
• The delay’s time display is in “beats” or “Hz”: for gear set in Hz rather than milliseconds, convert with 1000 ÷ ms (500 ms is 2 Hz)
• Not thinking in frames when syncing to video: video editors need milliseconds converted to frame counts (getting frame counts from BPM)

FAQ

How many milliseconds is a dotted-eighth delay at BPM 120?

375 ms. A quarter note is 60000 ÷ 120 = 500 ms, and 0.75 of that is 375 ms. For reference, an eighth note is 250 ms and a quarter note is 500 ms.

What’s the formula for calculating delay time from BPM?

A quarter note is “60000 ÷ BPM” ms. An eighth note is 0.5 times that, a sixteenth 0.25 times, a dotted eighth 0.75 times, and an eighth triplet one-third.

How many ms is a dotted eighth at BPM 128?

351.5625 ms (about 351.6 ms). A quarter note is 468.75 ms, and this is 0.75 of that. On gear that only accepts whole milliseconds, 351 or 352 is fine.

How do I calculate triplet delay times?

Take two-thirds of the original note length. An eighth triplet is two-thirds of an eighth note, which is one-third of a quarter note. At BPM 120 that’s 500 ÷ 3 ≈ 166.7 ms.

Which note value works best for vocal delay?

Quarter notes are common for ballads and eighth notes for up-tempo songs. Standard tricks include combining an eighth and a quarter on the left and right, and putting a high-cut on the delay so the words don’t get buried.