🥁 Metronome
Keep perfect time. Adjust BPM, tap your tempo, or pick a time signature — right in your browser.
📋 When to Use the Metronome
Use it whenever steady time matters more than feel: drilling scales and technical passages, locking in a tricky rhythm one notch at a time, or recording to a click so separate takes line up. Start a hair under the tempo you're aiming for, get it clean, then nudge the BPM up a few points and repeat — that slow ratchet is how difficult passages become reliable.
It's just as useful away from an instrument. Drummers and dancers use it to internalize a pulse, vocalists to pace phrasing, and anyone learning a piece can tap in a tempo they can't name. The accented downbeat and beat dots keep you oriented inside the bar, so you always know where "one" is.
⚙️ How the Metronome Works
A metronome is only as good as its timing, and that's harder in a browser than it looks. A naive version would fire a callback every beat with setInterval — but JavaScript timers are best-effort: the browser runs them when the main thread is free, so a background tab, a layout reflow, or a busy CPU nudges each tick a few milliseconds late. Those errors accumulate, and the beat audibly drifts.
This tool sidesteps that. It reads the Web Audio clock — a high-precision timeline driven by your sound hardware, independent of the main thread — and schedules each click at an exact timestamp slightly ahead of when it should sound. A lightweight loop wakes up every so often, looks a short window into the future, and queues any clicks due in that window with sample-accurate start times. Even if the loop itself runs a little late, the clicks were already booked against the audio clock, so the tempo stays rock-steady.
Each click is a short synthesized tone generated on the fly — no audio files to load. The downbeat of every measure is pitched higher and a touch louder to mark beat "one," while the swinging pendulum and beat dots are driven from the same clock so what you see matches what you hear. Tap tempo works in reverse: it measures the average time between your taps and converts that interval to BPM with the relationship BPM = 60,000 ÷ milliseconds-per-beat.
How to Use the Metronome
- Set your tempo — drag the BPM slider (40–208) or use the TAP button to tap your desired tempo. The BPM display updates in real time.
- Choose a time signature — select 2/4, 3/4, 4/4, or 6/8. The first beat of each measure gets an accented (higher) click, and the beat dots below show your position.
- Start the metronome — click ▶ or press the Spacebar. You'll hear rhythmic clicks and see the pendulum swing in sync with the beat.
- Practice and adjust — change tempo or time signature while playing. The metronome adapts seamlessly. Click ⏹ to stop.
Frequently Asked Questions
How accurate is an online metronome?
Because this tool schedules clicks against the Web Audio hardware clock rather than relying on JavaScript timers, its timing is sample-accurate — steady to well under a millisecond and on par with a dedicated hardware metronome. The one thing that can disturb it is an overloaded device, so closing heavy background tabs keeps it tight.
What do the BPM numbers mean, and what's a typical tempo?
BPM is beats per minute — 60 BPM is one beat per second, 120 is two. As a rough map: 40–60 is very slow (Largo), 66–76 Adagio, 76–108 Andante, 108–120 Moderato, 120–168 Allegro, and 168–208 Presto. Most pop and rock sits around 100–130. When learning a passage, practising slower than the target and building up beats rushing every time.
How does tap tempo work?
Tap the button steadily 3–4 times at the speed you have in mind. The tool measures the average gap between taps and converts it to BPM (60,000 divided by the milliseconds between beats). More taps give a more stable reading, which is handy for matching a song on the radio without knowing its tempo.
Why is the first beat of each bar accented?
The louder, higher click marks the downbeat — beat "one" — so you can feel where each measure begins. In 4/4 you'll hear the accent every four clicks, in 3/4 every three. That anchor is what lets you stay oriented in the bar instead of losing count, especially in odd or fast time signatures.
What do the time signatures (4/4, 3/4, 6/8) change?
The top number sets how many beats fall in each measure, which is how many clicks play before the accent comes back around. 4/4 is four beats per bar (most popular music), 3/4 is three (waltz feel), 2/4 is a brisk march, and 6/8 has a rolling, compound feel grouped in two. Switching one updates the beat dots so you can see the grouping.
Can I use it with headphones, or silently?
Yes to both. Audio plays through whatever output your device uses, so headphones work for private practice and a speaker works for a group. And because the swinging pendulum and flashing beat dots run off the same clock as the sound, you can follow the tempo by eye alone when you need to stay quiet.