How is tap tempo calculated?

Each tap is timestamped with performance.now() for sub-millisecond accuracy. The average inter-tap interval is computed as (last_tap - first_tap) / (tap_count - 1), then converted to BPM with the formula BPM = 60 000 / interval_ms. Using the average across all taps rather than just the last two intervals smooths out human timing imprecision.

What is the formula for note delay times?

One quarter-note beat lasts 60 000 / BPM milliseconds. All other note values are multiples of that beat: a whole note is 4x, a half note 2x, an eighth 0.5x, a sixteenth 0.25x, a 32nd 0.125x. A dotted note adds half its own value (1.5x), and a triplet note takes two-thirds of the straight value (2/3x).

How accurate is the browser metronome?

This tool uses the Web Audio API lookahead scheduler (25 ms poll, 100 ms schedule-ahead window) rather than setInterval alone. setTimeout/setInterval can drift by 15-100 ms under load; the Web Audio clock is tied to the audio hardware and stays within 1-2 ms. This matches the accuracy of many desktop DAW click-track outputs.

What is BPM and how is it used in music production?

BPM stands for Beats Per Minute — the number of quarter-note pulses in 60 seconds. It is the universal tempo reference: a DAW session grid, a drum machine pattern length, a delay plug-in sync value and a pitch-to-frequency mapping all derive from BPM. Producers set a project BPM first, then every element (loops, MIDI, automation) snaps to the same grid.

Why does dotted-note delay sound more musical?

A dotted quarter note lasts 1.5 beats. When a dotted-eighth delay (0.75 x beat) is set against a 4/4 groove it creates a three-against-four polyrhythm that feels like it is chasing the beat — the classic U2 / The Edge effect. The straight quarter note delay, by contrast, simply echoes every beat and can make the mix feel cluttered.

Can I use this tool offline?

Yes — once the page is loaded, everything runs in your browser with no network calls. The Web Audio engine, tap-tempo logic and all calculations are entirely client-side. You can bookmark the page and return to it even without an internet connection if your browser has cached the assets.

Metronome & BPM Tapper

A free, browser-based metronome and BPM tapper that does three things at once: it listens to your taps to detect tempo, drives a precision Web Audio click-track in any time signature, and generates a complete table of note-delay times in milliseconds — the numbers you need when dialling in delay and reverb pre-delay in a DAW.

How it works

Tap-tempo detection

Every tap is timestamped with performance.now(), which gives sub-millisecond resolution on modern browsers. The tool keeps a rolling window of up to 32 taps and resets the window if there is more than 2.5 seconds of silence (signalling the end of a phrase rather than a slow beat). The average interval is:

avg_interval = (last_tap_time - first_tap_time) / (tap_count - 1)

This multi-tap average is far more stable than a simple “last two taps” measurement. Converting to BPM uses the fundamental relationship:

BPM = 60 000 / avg_interval_ms

For example, if 8 taps span 2,800 ms, the average interval is 2 800 / 7 = 400 ms, giving 60 000 / 400 = 150 BPM — a brisk Allegro.

Web Audio metronome

The click-track uses the Web Audio API lookahead scheduler, the same technique recommended by Mozilla and used by professional browser-based DAWs. A setTimeout loop fires every 25 ms and schedules clicks up to 100 ms ahead using AudioContext.currentTime — a hardware-slaved clock that does not drift with CPU load. Each click is a short sine-wave burst: the downbeat (beat 1) plays at 1600 Hz, sub-beats at 880 Hz, both with a fast attack and 60 ms decay that mimics a classic drum-machine click.

Note-delay table

From the quarter-note beat duration Q = 60 000 / BPM ms, every standard note value is a rational multiple:

Note	Multiplier
Whole (1/1)	4 × Q
Half (1/2)	2 × Q
Quarter (1/4)	1 × Q
Eighth (1/8)	0.5 × Q
Sixteenth (1/16)	0.25 × Q
Thirty-second (1/32)	0.125 × Q

Dotted notes add half their base value (1.5× multiplier); triplet notes compress three into the space of two (2/3× multiplier). The Hz column is 1 000 / delay_ms, useful for setting tempo-synced LFOs in Hz mode.

Worked example

You are producing a track at 128 BPM (club Allegro / Vivace boundary).

One quarter-note beat: 60 000 / 128 = 468.75 ms.

Key delay values:

Dotted eighth note: 468.75 × 0.5 × 1.5 = 351.56 ms — the classic slapback delay
Eighth note triplet: 468.75 × 0.5 × 2/3 = 156.25 ms — creates a shuffle feel
Quarter note: 468.75 ms — straight echo on every beat
Whole note: 1 875 ms — long reverb pre-delay or riser timing

Tap the tool to 128 BPM with the Spacebar, then read all values directly from the table without doing any arithmetic.

Tempo names reference

Traditional Italian tempo markings correspond to BPM ranges: Grave (40-59), Largo (60-65), Larghetto (66-75), Andante (76-107), Moderato (108-119), Allegro (120-155), Vivace (156-175), Presto (176-199), Prestissimo (200+). The tool displays the correct name next to the slider so you can communicate tempo in classical terms as well as raw BPM.