How long is a beat at 120 bpm?

Half a second, so two beats a second. A bar of 4/4 takes two seconds, which works out at thirty bars a minute, and an eighth note is 250 milliseconds. The full table is below.

Is 120 bpm allegro or moderato?

The tool calls it Allegro. 120 is exactly where Moderato ends and Allegro begins on a printed metronome face, and every boundary here is resolved low-inclusive, so 120 is the first tempo of Allegro and 119 is the last of Moderato. Allegro runs from 120 to 168.

What music is at 120 bpm?

A brisk march is the traditional answer, and it is also the default tempo of most music software and a common landing spot for pop, house and disco. It is popular partly because the arithmetic is clean: half-second beats, two-second bars, and delay times that are round numbers of milliseconds.

What delay time should I use at 120 bpm?

A quarter-note delay is 500 ms, an eighth is 250 ms and a sixteenth is 125 ms, all in the table below. Those are the figures to type into a delay or a tremolo so it lines up with the beat rather than fighting it.

Does the click stay in time when the tab is busy?

Yes. Beats are booked on the audio hardware clock a tenth of a second ahead, the method browser sequencers use, and each beat time is accumulated from the previous one rather than read off the clock, so scheduling delays never get baked into the tempo. If the tab is put in the background long enough for whole beats to pass unscheduled, those beats are skipped rather than fired all at once, and the tool says how many it dropped.

Can I put an accent on the first beat?

It is on by default: the first beat of each bar is higher and louder. Beats per bar goes from 2 to 7, and the subdivision control adds eighths, triplets or sixteenths between the beats. There are three sounds to choose from, and all of them are generated in the browser rather than downloaded.

120 BPM Metronome

The metronome above is set to 120 beats per minute: two clicks a second, a bar of 4/4 every two seconds, and thirty bars a minute. It is the tempo of a brisk march and of a great deal of pop and dance music, and it sits at the very bottom of Allegro on the tempo scale. Press Start and it runs. The table below gives every note value at 120 bpm in seconds and milliseconds, computed from the interval the metronome plays on.

Allegro · 4/4120beats per minute

Tempo

Beats per bar

Subdivide

Sound

Accent first

Volume

70%

Stopped. Press Start, or the space bar, to hear 120 beats per minute.

Timing methodwhy it does not drift
Web Audio look-ahead scheduler: 100 ms window, 25 ms tick, beat times accumulated
Tap tempotap the button or press T in time
Tap the button, or press T, at least twice. The last 8 gaps between taps are averaged.
Soundclick, with the accent a higher pitch
A short burst of noise through a narrow filter, the sound of a mechanical metronome's escapement.
Keyboardhands stay on the instrument
Space start and stop ↑ ↓ one bpm ← → five bpm T tap

The shortcuts wake up once you have clicked or tabbed into the tool, and only while the metronome is on screen. Until then the space bar and the arrow keys scroll the page, the way they do everywhere else.

Tempo markings

The Italian markings and the beats per minute usually printed against them. They are a naming convention, not a measurement: composers used these words for two centuries before anyone attached numbers, and editions place the boundaries a few beats apart. The row matching your tempo is highlighted.

Marking	Beats per minute	Feel
Largo	40 to 59	very slow, broad
Larghetto	60 to 65	slow, a shade lighter than largo
Adagio	66 to 75	slow, at ease
Andante	76 to 107	walking pace
Moderato	108 to 119	moderate
Allegro	120 to 167	fast, bright
Vivace	168 to 175	lively
Presto	176 to 199	very fast
Prestissimo	200 and up	as fast as it will go

setInterval is not a metronome. A page timer fires late whenever the browser is busy, and the lateness accumulates, so a click driven by one is audibly behind after a few minutes. This schedules each click a tenth of a second ahead on the audio hardware's own clock, the technique browser sequencers use, and each beat time is worked out from the beat before it rather than from a fresh clock reading. That is what puts the beats 0.5000 seconds apart at 120 bpm and keeps them there. If the page is ever starved for longer than the look-ahead window, the beats that were lost are counted and shown rather than played late.

Accuracy. Beats are scheduled on the audio hardware clock a tenth of a second ahead, the method used by browser sequencers, so the pulse does not drift when the page is busy. Tap tempo averages your last eight taps. Below 20 and above 300 beats per minute is outside what this plays, and tapping cannot set anything slower than 30, because a gap over two seconds is read as a pause. Type those tempos instead.

Note lengths at 120 bpm

Computed from the interval the metronome actually schedules on: sixty seconds divided by the tempo, then by the subdivision. The quarter note is the beat. The millisecond column is the one to use for delay and tremolo times at this tempo.

Note value	Length in seconds	In milliseconds
Whole note, four beats	2 s	2000 ms
Half note, two beats	1 s	1000 ms
Quarter note, one beat	0.5 s	500 ms
Eighth note	0.25 s	250 ms
Eighth-note triplet	0.1667 s	166.67 ms
Sixteenth note	0.125 s	125 ms
One bar of 4/4	2 s	2000 ms

Common questions

How long is a beat at 120 bpm?: Half a second, so two beats a second. A bar of 4/4 takes two seconds, which works out at thirty bars a minute, and an eighth note is 250 milliseconds. The full table is below.
Is 120 bpm allegro or moderato?: The tool calls it Allegro. 120 is exactly where Moderato ends and Allegro begins on a printed metronome face, and every boundary here is resolved low-inclusive, so 120 is the first tempo of Allegro and 119 is the last of Moderato. Allegro runs from 120 to 168.
What music is at 120 bpm?: A brisk march is the traditional answer, and it is also the default tempo of most music software and a common landing spot for pop, house and disco. It is popular partly because the arithmetic is clean: half-second beats, two-second bars, and delay times that are round numbers of milliseconds.
What delay time should I use at 120 bpm?: A quarter-note delay is 500 ms, an eighth is 250 ms and a sixteenth is 125 ms, all in the table below. Those are the figures to type into a delay or a tremolo so it lines up with the beat rather than fighting it.
Does the click stay in time when the tab is busy?: Yes. Beats are booked on the audio hardware clock a tenth of a second ahead, the method browser sequencers use, and each beat time is accumulated from the previous one rather than read off the clock, so scheduling delays never get baked into the tempo. If the tab is put in the background long enough for whole beats to pass unscheduled, those beats are skipped rather than fired all at once, and the tool says how many it dropped.
Can I put an accent on the first beat?: It is on by default: the first beat of each bar is higher and louder. Beats per bar goes from 2 to 7, and the subdivision control adds eighths, triplets or sixteenths between the beats. There are three sounds to choose from, and all of them are generated in the browser rather than downloaded.

Beats are scheduled on the audio hardware clock a tenth of a second ahead, the method used by browser sequencers, so the pulse does not drift when the page is busy. Tap tempo averages your last eight taps.