Free Online Metronome — Tap Tempo

Practice and develop timing discipline with a precision online metronome built as a real mechanical instrument: drag the brass weight to set the tempo, watch the pendulum swing in lockstep with the audio clock, and read each measure as it is inscribed on the beat tape. Built for musicians, producers, audio engineers, and rhythm training.

The Instrument: Drag the Weight, Not a Slider

Physical metronomes are reciprocal devices — sliding the weight toward the pivot shortens the period, and the tempo rises. This tool preserves that behaviour. Grab the brass weight and slide it along the rod: the tempo scale is engraved in real BPM, so you set tempo the way a pianist would, not by typing numbers into a form.

The pendulum is not a decorative loop animation. Its angle is derived from the same Web Audio hardware clock that schedules the clicks, so the tick and the swing extreme are the same event, every beat, at any tempo. The escapement wheel advances exactly one tooth per beat, and the light under the base pulses with the downbeat.

Work quickly with the keyboard, too: ↑/↓ or ←/→ nudge the tempo by 1 BPM, hold Shift for ±5, T taps tempo, and Space starts or stops.

Stage Mode, Subdivisions & Shareable Tempos

• Stage mode — one tap turns the page into a full-viewport instrument. The pendulum grows to fill the screen for practice rooms and silent visual practice, and a screen wake lock keeps the display alive while you play. Press Escape to exit.
• Subdivisions — off, eighths, triplets, or sixteenths. Subdivision clicks sit at a softer level under the beat, while the downbeat accent stays on top, so swing and shuffle feels are easy to internalise.
• Shareable tempos — the URL carries your setup (?bpm=120&sig=4&sub=2), so a teacher can send a student an exact practice link. Your last settings are also remembered on this device.

The Lookahead Scheduler: Why Browser Clocks Matter

A common flaw in web-based music software is relying on window.setInterval() to trigger audio events directly. Because JavaScript runs in a single-threaded event loop alongside DOM rendering, page animations, and script execution, setInterval() triggers with noticeable jitter—frequently missing beats by 10 to 50 milliseconds.

Ordinary setInterval:
[ Beat 1 ] -------- [ Beat 2 ] ---- [ Beat 3 ] -------- [ Beat 4 ]  (Jitter & Drift!)

Web Audio Lookahead Architecture:
Main Thread Timer (25ms loop) ──▶ Queues beats into Web Audio Hardware Queue (100ms ahead)
Audio Hardware Engine         ──▶ Plays beats at exact sample clock timestamps (0.000ms drift)

This tool utilizes the Web Audio Lookahead Scheduler:

1. A lightweight background timer checks every 25 milliseconds whether any beats fall within the upcoming 100-millisecond scheduling window.
2. If upcoming beats are detected, OscillatorNode and GainNode events are scheduled using hardware timestamps via audioContext.currentTime.
3. Even if the browser encounters a momentary CPU spike or heavy layout rendering, the underlying audio subsystem plays the scheduled transients with zero timing drift.

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Tempo Markings & Practical BPM Ranges

Tempo marks communicate emotional character and performance velocity. Use this quick reference to navigate standard Italian musical tempos:

Italian Marking	BPM Range	Typical Feel & Repertoire
Grave / Largo	30–59 BPM	Solemn, expansive, sustained adagios and meditative cadences
Adagio	66–75 BPM	Slow and expressive; lyrical movements
Andante	76–107 BPM	At a walking pace; natural, flowing tempo
Moderato	108–119 BPM	Moderate speed; classical sonata allegros
Allegro	120–155 BPM	Fast, cheerful, and bright; modern pop, rock, and standard marches
Vivace	156–175 BPM	Lively, brisk, and animated; fast dance styles
Presto / Prestissimo	176–240 BPM	Extremely fast, virtuosic runs, bluegrass, and uptempo bebop

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Time Signatures & Accent Schemes

Accents help ears lock into the pulse of a song. Choose between standard meters:

• Straight Pulse (1 Beat): Unaccented isochronous click. Ideal for speed-burst drills, polyrhythmic independence, or neutral metronome practice.
• 2/4 Meter (Duple): Strong accent on beat 1 (ONE - two). Used in traditional marches, bossa nova, and fast polkas.
• 3/4 Meter (Triple): Strong accent on beat 1 (ONE - two - three). The classic foundation of waltzes, minuets, and lyrical folk ballads.
• 4/4 Meter (Common Time): Primary accent on beat 1, subtle secondary accent on beat 3 (ONE - two - THREE - four). The backbone of rock, pop, jazz, and classical symphonies.
• 6/8 Meter (Compound Duple): Primary accent on beat 1, secondary accent on beat 4 (ONE - two - three - FOUR - five - six). Perfect for Celtic jigs, blues shuffles, and rock ballads with a triplet swing.