How accurate is it, honestly?

The scheduling is sample-accurate: clicks are placed on the browser's audio clock, which does not wobble the way JavaScript timers do, and the beat times are computed rather than accumulated so error cannot build up. What the page cannot control is your output chain — Bluetooth headphones add a fixed delay of anywhere from 40 to 300 milliseconds. A fixed delay shifts every click equally, so the tempo stays exact; only side-by-side comparison with another sound source would expose it.

Does it keep clicking if I switch tabs?

Started audio generally keeps running in a background tab, but browsers throttle background pages aggressively enough that this is not the mode to rely on for practice. Keep the tab in front — the screen is held awake while the metronome runs, precisely so a phone on a music stand stays on.

Why do I have to press start before it makes sound?

Browsers require a tap before a page may produce audio — an autoplay rule that protects you from every other website. The start button is that tap. After it, tempo and meter changes take effect without stopping.

What do the tempo numbers mean in practice?

BPM is beats per minute: 60 is one click a second, 120 is two. As rough musical anchors: 60–76 is largo to adagio territory, 76–108 andante, 108–132 moderato to allegro, 168 and up presto. Start slower than the record and creep up — the metronome remembers nothing between sessions, but your hands will.

Is it free, and does it upload anything?

Free, no account, no ads between you and the beat. It listens to nothing — there is no microphone involved — and your files are never uploaded, because no files are involved at all. The page makes sound; that is the whole of it.

Online metronome

A metronome has one job: the next click lands exactly where the last one promised. Most metronome pages get this wrong in a way you can feel — they time each click off a browser timer, every timer fires slightly late, and the lateness compounds until the beat wanders. This one schedules every click on the audio clock, at times computed rather than accumulated, so an hour of practice ends on the same grid it started on.

How to use the metronome

Set your tempo

Type nothing: nudge with the buttons, drag the slider, or tap the tempo in on the Tap button.
Pick the meter

2/4, 3/4, 4/4 and 5/4, or the compound 6/8, 7/8, 9/8 and 12/8 — the first beat of each bar is accented and drawn larger.
Press start

It begins immediately. There is nothing to download, and the screen stays awake while it runs.

What you get

The beat cannot drift, by construction

Every click's time is computed as beat-number times beat-length from a fixed starting point, then handed to the audio clock — the sample-accurate one, not the sloppy timer one. A slow tab delays the scheduling, never the sound. The arithmetic is unit-tested across a simulated hour at 137 BPM: every beat lands where the arithmetic says it will.

Tap the tempo you mean

Tap along to the song or the feel in your head and the metronome takes the tempo from your taps — averaged over the last few so one clumsy tap does not yank the reading. There is also a full-page tap tool if measuring a tempo is all you came for.

Accents that follow the meter

The first beat of every bar clicks higher and lights larger, from 2/4 up to 12/8. In the compound meters — 6/8, 7/8, 9/8, 12/8 — each group start gets a middle accent too, so 7/8 pulses as 2+2+3. Changing meter mid-run keeps the pulse — the bar simply regroups around it.

Starts instantly, works offline

The click is synthesized in the page — no samples to fetch, no model, nothing to wait for. Once loaded it runs with the wifi off, and it never asks for your microphone: this page only makes sound.

Questions about the metronome

How accurate is it, honestly?: The scheduling is sample-accurate: clicks are placed on the browser's audio clock, which does not wobble the way JavaScript timers do, and the beat times are computed rather than accumulated so error cannot build up. What the page cannot control is your output chain — Bluetooth headphones add a fixed delay of anywhere from 40 to 300 milliseconds. A fixed delay shifts every click equally, so the tempo stays exact; only side-by-side comparison with another sound source would expose it.
Does it keep clicking if I switch tabs?: Started audio generally keeps running in a background tab, but browsers throttle background pages aggressively enough that this is not the mode to rely on for practice. Keep the tab in front — the screen is held awake while the metronome runs, precisely so a phone on a music stand stays on.
Why do I have to press start before it makes sound?: Browsers require a tap before a page may produce audio — an autoplay rule that protects you from every other website. The start button is that tap. After it, tempo and meter changes take effect without stopping.
What do the tempo numbers mean in practice?: BPM is beats per minute: 60 is one click a second, 120 is two. As rough musical anchors: 60–76 is largo to adagio territory, 76–108 andante, 108–132 moderato to allegro, 168 and up presto. Start slower than the record and creep up — the metronome remembers nothing between sessions, but your hands will.
Is it free, and does it upload anything?: Free, no account, no ads between you and the beat. It listens to nothing — there is no microphone involved — and your files are never uploaded, because no files are involved at all. The page makes sound; that is the whole of it.

Tuning first? The instrument tuner runs on the same no-download model. Found the tempo by ear? Tap it in and it opens here already set. And when the song is too fast to keep up with, slow it down without changing the pitch.