Online Metronome

How to set up and use the metronome

1. Set the tempo with the slider (30 to 300 BPM) or fine-tune with the -1, +1, -5 and +5 buttons. The big number is the current BPM, and a word beside it shows the matching tempo name.
2. Choose beats per bar, from 2 to 7. A row of squares appears, one per beat.
3. Press Start. The first beat of every bar sounds higher and sharper than the others, so you can hear where the bar begins. The square for the current beat lights up. Press the same button (now showing Stop) to end.
4. Changing the BPM while it is running takes effect from the next click, so you can speed up or slow down without stopping.

Finding a song's tempo with tap tempo

Press Tap tempo in time with the music. From the second tap onward the tool measures the gaps between taps and sets the BPM to 60,000 divided by the average gap in milliseconds. Example: taps 500 ms apart average to 120 BPM; taps 750 ms apart give 80 BPM.

Only the last eight taps are averaged, so a slightly wobbly start fades out of the result as you keep going. If you pause for more than two seconds, the next tap starts a new measurement. Four to eight steady taps is usually enough. The result is rounded to a whole BPM.

How the timing stays steady

Browsers' ordinary timers can drift or stall when a page is busy. This metronome therefore uses a look-ahead scheduler: a timer wakes every 25 milliseconds and schedules every click that falls within the next 150 milliseconds on the audio hardware clock. The sound itself is a short sine-wave blip, about 50 ms long, at 1600 Hz on the first beat and 1000 Hz on the others. Because each click is placed in the audio timeline in advance, small delays in the page do not change when you hear it. The visual squares use a separate timer, so on a very slow device the light may lag slightly behind the sound; trust your ears.

Tempo names in this tool

The label beside the BPM follows these ranges: below 60 Largo, 60 to 75 Adagio, 76 to 107 Andante, 108 to 119 Moderato, 120 to 155 Allegro, 156 to 199 Vivace, and 200 or more Presto. These are conventional rules of thumb and different books draw the borders a little differently. Composers' markings are guidance, not a precise instruction.

Practice ideas

• Slow-to-fast ramp: play a passage at 60 BPM, then raise it by 4 to 5 BPM each time you get it right three times in a row. Write down the tempo you reached so the next session starts from there.
• Subdivision check: set 60 BPM and play eighth notes or triplets against each click. If you rush between clicks, you will hear the click arrive "early" against your notes.
• Odd meters: pick 5 or 7 beats per bar for pieces in 5/4 or 7/8-style groupings. The accent marks only the start of the bar, so you will need to count the internal groups (for example 3+2 or 2+2+3) yourself.
• Half-tempo trick: for fast pieces, set the metronome to half speed and treat each click as a larger pulse. It trains you to feel the phrase, not every note.
• Drummers and DJs: use tap tempo to approximate a track's BPM, then confirm by running the metronome against it for a minute and listening for drift.

Limits to know

• The meter changes the number of beats per bar only. There is no separate setting for note value, swing or subdivisions, and every beat is the same volume except for the accent.
• Tap tempo reflects your tapping accuracy. A recording with a human drummer is not perfectly constant either, so a reading of 97 or 103 for a "100 BPM" song is normal.
• Audio output goes through your device speaker or headphones. Bluetooth headphones can add a delay of a few tenths of a second, which affects when you hear the click but not the spacing between clicks.
• Browsers keep sound blocked until you interact with the page, which is why audio begins only after you press Start.

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