Tempo, time signature, subdivisions and an accented downbeat. Nothing to install, nothing to sign up for.
It gives you a steady pulse to play against, with the four things a practising musician needs: a tempo you can set or tap in, a bar length so you can hear where one is, an accent on the downbeat so you do not lose your place, and subdivisions for the passages where the problem is between the beats.
Web pages have a reputation for sloppy metronomes, and it is deserved when they are built the obvious way. A timer that fires every beat and plays a click is at the mercy of the main thread, which is also busy with layout and garbage collection, so clicks land tens of milliseconds late at random. That is audible, and maddening to play to.
This page deliberately does not load the synthesis library the Gusta Music studio itself runs on. A metronome needs one oscillator and a scheduler, and somebody who searched for a metronome should not download a whole audio engine to get one.
Output latency is real and it is not the metronome's fault: Bluetooth headphones can add 150 milliseconds or more between the click and your ear. The pulse is still perfectly even, it is simply late as a whole, which matters when you play along with something else and does not when the metronome is your only reference. Use wired headphones if you are recording. On a phone, switching apps suspends the tab and stops the click. And tap tempo can only average what you gave it, so tap for a few bars rather than twice.
This one does not. A naive version plays a click each time a setInterval fires, inheriting every millisecond of jitter the browser has. This one uses setInterval only to look ahead: every 25 milliseconds it asks which clicks fall in the next tenth of a second and books them on the Web Audio clock at exact times. The audio hardware plays them to the sample, so a stalled main thread costs you nothing.
Tap the Tap button in time with the music, at least twice. The tempo is the average of your last taps, up to six of them, and it resets if you pause for more than two and a half seconds. Four taps is usually enough to land within a beat per minute.
Beats per bar is the top number of a time signature: how many clicks pass before the accent comes round again. The note value is the bottom number: on 4 the pulse is a quarter note, on 8 an eighth note, so 6/8 at 120 clicks twice as fast as 6/4 at 120. Subdivision adds quieter clicks between the beats for practising eighths, triplets or sixteenths.
Browsers require a user gesture before any page can make sound, which is an autoplay rule rather than anything specific to this page. Pressing Start is that gesture, and the space bar starts and stops it once the page has focus.
Once loaded it needs no network at all, so it keeps working offline. It works on phones and tablets, though a phone browser usually stops the audio if you switch apps, since backgrounded tabs are suspended to save battery.
Slower than feels satisfying. Set it to the fastest tempo at which you can play a passage cleanly twice in a row, stay there until it is boring, then move up by about five beats per minute. If you are learning a song, run the BPM detector on it first so you know the target.
Gusta Music is the free browser studio these tools came out of: multitrack timeline, sampling, mic recording with a count in, and an AI copilot that edits the song with you instead of generating one for you. Your work stays yours.
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