This BPM calculator deals with musical tempo — beats per minute in the sense a metronome means it, not the sense a fitness tracker means it. It does two related jobs. It works out the tempo of a piece of music from your tapping or from a beat count against a stopwatch, and it converts any tempo into the exact duration of every common note value in milliseconds, seconds, hertz and audio samples.
Those millisecond figures are the reason most people arrive here. Delay pedals, plugin delays, tremolo rates, gate times, LFO speeds and sidechain release times are all set in milliseconds, while the music they have to sit inside is measured in beats. Arb Digital built this as part of a free tools library used by people who need a number quickly and correctly, and tempo maths is one of those places where a rounding error of a few milliseconds is genuinely audible.
What This BPM Calculator Does
Set a tempo directly, tap it in, or derive it from a beat count. The headline figure is the length of one beat — one quarter note in common time — shown in milliseconds and seconds. Around it you get the tempo itself, the length of a full bar at your chosen time signature, the beat expressed as a frequency in hertz, and the number of audio samples one beat occupies at your project's sample rate.
Beneath that is the note-length table: whole, half, quarter, dotted eighth, eighth, eighth-note triplet and sixteenth, each with its duration in milliseconds and a bar showing its length relative to a whole note. That table is what you copy into a delay plugin that has no tempo-sync switch, or into a hardware unit that only accepts raw milliseconds.
Worth stating clearly, because the search term is ambiguous: this page is about music. If you are looking for pulse, resting heart rate or exercise intensity, the heart rate zone calculator, the max heart rate calculator and the target heart rate calculator cover that ground properly and this one does not touch it. For pitch rather than rhythm, the note frequency converter handles the conversion between note names and hertz.
How to Use It
- Get the tempo in. Type it if you already know it. Otherwise press the tap button in time with the music at least four times — accuracy improves steadily up to about eight taps and then plateaus.
- Or count beats against a clock. Start a stopwatch, count beats for fifteen seconds or more, enter both numbers and press the beat-count button. This is more reliable than tapping for slow or rubato music.
- Set the beats per bar. This only affects the bar-length figure. Leave it at 4 unless you are working in 3/4, 5/4, 7/8 or something more unusual.
- Choose your sample rate if you need sample-accurate offsets for editing or for a plugin that reports delay in samples rather than milliseconds.
- Read the note table. Take the millisecond value for the note value you want and enter it into your delay, gate or LFO. Round to the nearest whole millisecond only if your device will not accept decimals.
The Formula / How It's Calculated
Everything follows from a single division. There are 60,000 milliseconds in a minute, so one beat in milliseconds = 60,000 ÷ BPM. Every other figure is that number scaled.
A whole note is four beats, so it is four times the beat length. A half note is two. An eighth note is half a beat. A sixteenth is a quarter of a beat. A dotted note is 1.5 times its plain value, because the dot adds half again. A triplet is two-thirds of its plain value, because three of them occupy the space of two. A bar is the beat length multiplied by the beats per bar.
Worked example at the tempo this page loads with. At 120 BPM, one beat is 60,000 ÷ 120 = 500.00 ms. A 4/4 bar is 4 × 500 = 2,000 ms. An eighth note is 250 ms, a sixteenth is 125 ms. The dotted eighth is 250 × 1.5 = 375 ms. The eighth-note triplet is 250 × 2/3 = 166.67 ms. As a frequency, one beat every 0.5 seconds is 1 ÷ 0.5 = 2.00 Hz, which is the number you would enter into an LFO with a hertz control. At 44,100 samples per second, one beat occupies 44,100 × 0.5 = 22,050 samples.
The tap-tempo maths is an average, not a guess at your last interval. The tool records the time of each tap, takes the gaps between consecutive taps, averages the most recent eight of them, and converts that average interval to BPM with 60,000 ÷ average. Averaging is what makes tap tempo usable: any single tap can be 30 ms early, but the errors mostly cancel across eight of them. Taps more than three seconds apart start a fresh measurement, so you can restart without clearing.
Why Delay Times Get Set to the Wrong Note Value
Most delay settings that sound wrong are on the correct note value for the wrong reason. A quarter-note delay repeats exactly on the beat, which reinforces the rhythm but can make a busy arrangement feel cluttered because every repeat lands on top of something. An eighth-note delay doubles the subdivision, which is why it disappears into fast material. The dotted eighth — three sixteenths, or 375 ms at 120 BPM — is the one that produces the familiar cascading effect, because its repeats consistently fall between the beats and then realign every three beats.
Triplets create a different problem. An eighth-note triplet at 166.67 ms cannot be entered accurately into a device that only accepts whole milliseconds; rounding to 167 ms drifts by 2 ms per repeat, which is inaudible on two repeats and clearly out of time by twenty. If your unit takes only integers, prefer note values that divide cleanly at your tempo, or shift the tempo by a fraction of a BPM so the triplet lands on a whole number.
There is one more trap: not every delay control means the same thing. Some plugins set the time between repeats, others set the total time before the first repeat, and a few set feedback in a way that changes the perceived spacing. Check what happens to the first repeat when you double the time before you trust a number you calculated.
Tempo Sync, MIDI Clock and Why Sync Sometimes Drifts
Any modern digital audio workstation will sync a delay to the project tempo without you touching a millisecond figure, so it is worth knowing when the manual number is still the better choice. It is better whenever the tempo is not constant, whenever the device is outside the DAW, and whenever you want a delay that deliberately does not match the grid.
When devices do sync, they usually do it over MIDI clock, a stream of timing messages defined in the MIDI 1.0 core specifications published by the MIDI Association. Ableton's reference material on synchronising with Link, Tempo Follower and MIDI describes the clock as a metronome ticking at a fast, tempo-dependent rate, which is exactly why sync can feel unstable: the receiving device is continuously inferring a tempo from the arrival times of those ticks, and any jitter in the transport shows up as tempo wobble. Network-based sync protocols exist largely to solve that problem.
The practical rule is that a millisecond value never drifts. If you have a fixed-tempo track and a hardware delay, entering the number from the table is more stable than clocking the pedal, and it fails in a predictable way if the tempo ever changes.
Half-Time, Double-Time and the Tempo Nobody Agrees On
Tap tempo will happily report 85 BPM for a track that a DJ software will label 170. Neither is wrong. Tempo is a description of where you feel the pulse, and a great deal of music supports being counted at half or double the notated rate. Drum and bass sits around 174 BPM but has a half-time feel near 87; a slow hip-hop beat notated at 70 BPM is often counted at 140 in production software.
This matters for delay settings because a quarter note at 85 BPM is a half note at 170. If your calculated delay sounds twice as long or half as long as you expected, you and your source have simply chosen different pulses — halve or double the tempo and recalculate rather than assuming the maths failed. When you need the tempo to match another piece of software, match the convention that software uses rather than the one your foot chose.
The same ambiguity affects time signature. A track in 6/8 can be counted as six eighth-note beats or as two dotted-quarter beats, and the bar length differs by nothing while the beat length differs by a factor of three. The beats-per-bar selector here changes only the bar figure, so pick the count you are actually working in.
Getting an Accurate Tempo From a Recording
Tapping is fast, but it has a floor of about one BPM of accuracy for most people, and that is not enough for a loop that has to run for four minutes without drifting. The beat-count method is better: count a known number of beats across a long span and divide. Over 32 beats in 16 seconds you get 32 ÷ 16 × 60 = 120 BPM, and an error of a tenth of a second on the stopwatch moves the answer by less than one BPM.
For exact work, measure across the longest span you can. Find the first beat of bar 1 and the first beat of bar 33 in an audio editor, take the time between them, and divide by 128 beats. Any timing error is then spread across 128 beats instead of four, which is how you resolve tempos to two decimal places. If the result is something like 119.88 rather than 120, the recording was probably made on analogue tape or resampled at a slightly different rate — a small ratio error, and the percentage change calculator will tell you how far off it is.
Tempo also converts into other time units directly. The time converter moves between milliseconds, seconds and minutes, the frequency converter handles hertz against other rate units, and the unit converter covers the general case.
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Browse Free Tools Talk to Arb DigitalCommon Mistakes to Avoid
- Tapping only two or three times — a single mistimed tap dominates the average. Four is the minimum and eight is much better.
- Confusing the dotted eighth with the eighth — the dotted value is 1.5 times longer, and that difference is the whole character of the effect.
- Rounding triplet times to whole milliseconds — a 0.33 ms error per repeat is inaudible once and obvious after twenty repeats.
- Assuming your tempo matches the software's — half-time and double-time readings are both legitimate, so check which pulse the other tool is counting.
- Setting a delay by ear at the wrong tempo — if the project tempo changes later, every manually entered millisecond value is now wrong and none of them will warn you.
Related Free Tools From Arb Digital
Use the note frequency converter for pitch rather than rhythm, the frequency converter for hertz against other rate units, and the time converter to move between milliseconds, seconds and minutes. For anything to do with pulse rather than tempo, use the heart rate zone calculator or the max heart rate calculator instead. Everything else is in the free online tools hub.
Frequently Asked Questions
No. This page handles musical tempo — beats per minute as a metronome measures it — and the note durations that follow from it. For pulse and exercise intensity, use the heart rate zone calculator or the max heart rate calculator instead.
Divide 60,000 by the tempo. At 120 BPM one beat is 60,000 ÷ 120 = 500 ms. Halve that for an eighth note, quarter it for a sixteenth, multiply by 1.5 for a dotted value and by two-thirds for a triplet.
Four is the minimum for a usable reading and about eight gives most of the accuracy you can get by tapping. The tool averages the intervals between your most recent eight taps, so individual early or late taps largely cancel out.
Multiply the eighth-note length by 1.5. At 120 BPM the eighth is 250 ms, so the dotted eighth is 375 ms. Its repeats land between the beats rather than on them, which is why it sounds like a cascade rather than an echo.
Because tempo depends on which pulse you count. A half-time feel at 85 BPM is the same music as 170 BPM counted at the faster subdivision. Halve or double your figure to match whatever convention the other tool uses.
LFOs, tremolos and auto-pan effects are often set in hertz rather than note values. One beat every 0.5 seconds is 2 Hz, so entering 2 Hz gives a cycle per beat at 120 BPM. Halve the hertz figure for a cycle every two beats.
Measure across a long span. Find the first beat of two bars far apart in an audio editor, divide the elapsed time by the number of beats between them, and convert. Spreading the measurement error across 128 beats instead of four is what buys the precision.
This tool performs musical tempo arithmetic only. It is not a heart rate or fitness measurement and must not be used to assess pulse, exercise intensity or any aspect of health.
