How is BPM converted to a delay time in milliseconds?

The formula is delay (ms) = 60000 divided by BPM, multiplied by the note-value multiplier. A quarter note has a multiplier of 1, so at 120 BPM one quarter-note delay is 60000 / 120 = 500 ms. An eighth note is half that (250 ms). A dotted eighth note is 1.5 times an eighth note (375 ms). A triplet eighth is two-thirds of an eighth note (166.67 ms).

What is the famous dotted-eighth delay trick?

Setting a delay to the dotted-eighth note time creates a syncopated, galloping repeat that sits between the beats. It was popularised by U2 guitarist The Edge. At 120 BPM the dotted-eighth delay is 375 ms. Find that row in the BPM to delay table and press copy, then paste it into your plug-in.

How does the tap-tempo detection work?

Each time you press the TAP button the tool records the timestamp to within a millisecond using the browser performance timer. It keeps the most recent 8 tap intervals, averages them, and divides 60000 by the average to get the BPM. A gap of more than 3 seconds resets the session so you can start fresh.

What does the Hz column mean?

The Hz value is the reciprocal of the delay time (1000 divided by the milliseconds). It tells you the rate of that note value in cycles per second, which is useful when setting tempo-synced LFO rates on synthesisers or tremolo effects that accept frequency rather than time.

How does the feedback decay table work?

After the original signal plays, the delay unit feeds a percentage of the output back into the input. After n echoes the amplitude is feedback raised to the power n. For example, at 60% feedback the first echo is 60% of the original, the second is 36%, the third 21.6%, and so on. The tool solves for how many repeats occur before the amplitude drops below the dB threshold you set, typically -60 dB (one-millionth of the original).

How do I reverse-engineer a tempo from a delay time on old hardware?

Switch to the Delay time to BPM mode, enter the millisecond value shown on the hardware, and select which note value that time is supposed to represent. The tool calculates the matching BPM so you can set your DAW or drum machine to the same tempo and lock everything to the grid.

Is this tool accurate enough for professional use?

Yes. All arithmetic is done in double-precision floating point and results are rounded to 2 decimal places for display. The core formula (60000 / BPM) is the same one used in DAWs, hardware sequencers and every professional delay calculator. Results match industry-standard references such as the tables printed in tape-delay manuals and modern DAW sync utilities.

BPM Delay Calculator

A BPM delay calculator built for musicians, producers, mixing engineers and sound designers who need tempo-accurate delay times — and more. It covers four workflows in one tool: converting a tempo to a full table of note-length delay times, reversing that calculation to find the BPM that matches a hardware delay setting, detecting tempo by tapping along to a track, and modelling exactly how many echoes a feedback percentage produces before silence.

How it works

Converting BPM to delay time

Everything starts from the length of one quarter-note beat:

beat (ms) = 60,000 / BPM

Every other note value is a multiple of that beat. A whole note lasts four beats (x4); a half note lasts two beats (x2); an eighth note is half a beat (x0.5); a sixteenth is a quarter of a beat (x0.25). Dotted notes extend the straight value by 50% (x1.5). Triplet notes compress three notes into the space of two, giving a multiplier of 2/3.

The tool computes twelve note values — whole, half, dotted quarter, quarter, quarter triplet, eighth, dotted eighth, eighth triplet, sixteenth, dotted sixteenth, sixteenth triplet and thirty-second — and shows each one in milliseconds and in Hz. A copy button next to each value lets you paste the number directly into a plug-in.

Reverse mode: delay time to BPM

If you already have a delay time — perhaps from a vintage hardware unit, a sample or a field recording — you can work backwards:

BPM = (60,000 / delay in ms) x note multiplier

Select the note value that delay is meant to represent and the tool returns the matching BPM. Once you know the tempo you can set your DAW session to match and put everything on the grid.

Tap tempo detection

The tap-tempo panel uses the browser performance.now() timer for sub-millisecond accuracy. Tap at least twice; the tool averages the last eight intervals to smooth out inconsistent taps. A gap larger than three seconds resets the session automatically. After four or more taps the average is stable enough for professional use. The detected BPM feeds straight into the delay table below it.

Feedback decay modelling

Every delay unit has a feedback control that recycles the output back to the input. After n echoes the amplitude is:

amplitude(n) = feedback_fraction ^ n

where feedback_fraction is the percentage divided by 100. The tool counts repeats until the amplitude drops below the threshold you specify (e.g. -60 dB) and builds a table showing the time-stamp and level of every echo. This is useful for setting decay times on convolution reverbs, designing rhythmic gates and understanding how long a long reverb tail really is.

Worked example

Suppose you are working at 95 BPM and want to add a delay that feels wide and syncopated without cluttering the mix. The classic approach is a dotted-eighth delay:

Enter 95 in the BPM field.
Read the dotted-eighth row: 473.68 ms.
Paste that value into your delay plug-in.
Set feedback to 35% and switch to the Feedback decay panel. At that setting with a -60 dB threshold you will see 7 echoes spread over about 3.3 seconds — plenty of texture without washing out the next bar.

BPM	Note value	Delay
120	Quarter (1/4)	500 ms
120	Dotted eighth (1/8.)	375 ms
120	Eighth triplet (1/8T)	166.67 ms
95	Dotted eighth (1/8.)	473.68 ms
140	Eighth (1/8)	214.29 ms

Formula notes

The core relationship is simply: frequency (Hz) and tempo (BPM) are both rates, so the bridge between them is the fixed constant 60,000 (the number of milliseconds in a minute). All note-value multipliers cascade from that single calculation. The Hz column uses 1000 / ms because there are 1,000 milliseconds in a second.

The feedback decay formula is pure geometric-series mathematics: if each repeat is a fraction f of the previous, after n repeats the amplitude is f to the power n. Converting to decibels uses 20 log10(f^n) = 20n log10(f). All calculations run entirely in your browser — nothing is uploaded or stored.