What a BPM calculator does
BPM is the number of beats in one minute. A minute holds 60,000 milliseconds, so one beat lasts 60,000 divided by the BPM. At 120 BPM that is 500 ms. At 90 BPM it is about 666.7 ms. Every other time value in this page is a multiple or a fraction of that number.
Plugins and hardware often ask for time in milliseconds or in Hz, not in beats. A sync button helps in a DAW, but it does not exist on a pedal, on an old rack unit or in a video editor. Having the figure in front of you means you can set it anywhere.
The calculator shows four results for the tempo you enter.
- Milliseconds per beat. The length of a quarter note.
- Milliseconds per bar. Four beats, so 4/4 time is assumed.
- Beat frequency in Hz. How many beats happen each second, which is BPM divided by 60.
- Length of 8 bars. A handy figure for loops, intros and sample-length planning.
Here are the five presets, worked out by hand so you can check the tool.
| BPM | ms per beat | ms per bar (4/4) | Beat Hz | 8 bars |
|---|---|---|---|---|
| 90 | 666.7 | 2666.7 | 1.5 | 21.3 s |
| 120 | 500 | 2000 | 2 | 16 s |
| 128 | 468.8 | 1875 | 2.13 | 15 s |
| 140 | 428.6 | 1714.3 | 2.33 | 13.7 s |
| 174 | 344.8 | 1379.3 | 2.9 | 11 s |
The formulas behind the numbers
Three short formulas cover everything the calculator does. You can run them on any phone calculator if you ever need to.
- Milliseconds per beat = 60000 / BPM.
- Dotted note = straight note x 1.5. A dot adds half the note's length.
- Triplet note = straight note x 2/3. Three triplet notes fit in the space of two straight ones.
To get other note values, scale the quarter note. A half note is two beats, an eighth is half a beat, a sixteenth is a quarter of a beat, and so on. A whole note in 4/4 fills the full bar.
| Note value | Fraction of a beat | Example at 120 BPM |
|---|---|---|
| 1/1 (whole) | 4 beats | 2000 ms |
| 1/2 (half) | 2 beats | 1000 ms |
| 1/4 (quarter) | 1 beat | 500 ms |
| 1/8 (eighth) | 1/2 beat | 250 ms |
| 1/16 (sixteenth) | 1/4 beat | 125 ms |
| 1/32 (thirty-second) | 1/8 beat | 62.5 ms |
Frequency is the inverse of time. A 500 ms cycle repeats twice per second, so it is 2 Hz. Divide 1000 by the millisecond figure and you have Hz. That is how the table below turns delay times into LFO rates.
Note values: straight, dotted and triplet
This is the full table the calculator builds for your tempo. The figures here are for 120 BPM, so you can compare them with what the tool shows. The Hz columns are for LFO sync: set the LFO rate to that number and one cycle takes exactly one note value.
| Note | Straight ms | Dotted ms | Triplet ms | Straight Hz | Dotted Hz | Triplet Hz |
|---|---|---|---|---|---|---|
| 1/1 | 2000 | 3000 | 1333.3 | 0.5 | 0.333 | 0.75 |
| 1/2 | 1000 | 1500 | 666.7 | 1 | 0.667 | 1.5 |
| 1/4 | 500 | 750 | 333.3 | 2 | 1.333 | 3 |
| 1/8 | 250 | 375 | 166.7 | 4 | 2.667 | 6 |
| 1/16 | 125 | 187.5 | 83.3 | 8 | 5.333 | 12 |
| 1/32 | 62.5 | 93.8 | 41.7 | 16 | 10.667 | 24 |
Straight notes feel square and steady. Dotted notes land a little late and create the bouncy, rolling feel of a dotted-eighth delay. Triplets divide the beat in three and give a swinging, shuffled pulse. Mixing a straight kick with a triplet hi-hat delay is a classic way to add movement.
Delay times worked out for 120 and 128 BPM
Delay is where most people reach for a calculator. A delay set to a note value repeats in time with the track, so the echoes feel like part of the groove instead of a smear on top. These are the three most used note values at the two most common dance tempos.
| Note | 120 straight | 120 dotted | 120 triplet | 128 straight | 128 dotted | 128 triplet |
|---|---|---|---|---|---|---|
| 1/4 | 500 | 750 | 333.3 | 468.8 | 703.1 | 312.5 |
| 1/8 | 250 | 375 | 166.7 | 234.4 | 351.6 | 156.3 |
| 1/16 | 125 | 187.5 | 83.3 | 117.2 | 175.8 | 78.1 |
All values are milliseconds. A few quick rules of thumb:
- A 1/4 delay gives clear, spaced echoes that suit slow vocals and sparse lead lines.
- A dotted 1/8 delay is the classic guitar and synth setting. It fills the gaps between beats without crowding them.
- A 1/16 delay thickens the sound and starts to act like a short slap or a chorus.
- Use feedback sparingly. Two or three repeats are often enough to feel the rhythm.
If your plugin only accepts whole milliseconds, round to the nearest integer. A rounding error of half a millisecond is far below what the ear can hear as a timing shift.
Reverb pre-delay and decay
Pre-delay is the gap between the dry sound and the first reflection. A short gap keeps a vocal or snare clear before the reverb blooms behind it. Tying the pre-delay to the tempo makes the tail feel like it belongs to the song. The calculator shows a reverb card with pre-delay at 1/64 and 1/32 of a whole note.
| BPM | Pre-delay 1/64 (ms) | Pre-delay 1/32 (ms) |
|---|---|---|
| 90 | 41.7 | 83.3 |
| 120 | 31.3 | 62.5 |
| 128 | 29.3 | 58.6 |
| 140 | 26.8 | 53.6 |
| 174 | 21.6 | 43.1 |
The card also suggests decay times by space: room, plate and hall. As a general guide, a small room decays in under a second, a plate in one to two seconds, and a hall in two to three or more. Fast tempos need shorter tails, otherwise the reverb from one beat is still ringing when the next one arrives.
A good trick is to choose a decay that fades out just before the next downbeat. At 120 BPM a bar lasts two seconds, so a tail around 1.5 seconds clears before the bar ends.
More ways to use the numbers
Delay and reverb are only the start. Any setting that is measured in time can be locked to the tempo.
- Compressor release. Set the release to an eighth or sixteenth note so gain recovers in time with the beat. At 120 BPM, 250 ms is a 1/8 release. The compressor then pumps with the groove.
- LFO rates. Use the Hz column. A 1/8 LFO at 120 BPM runs at 4 Hz, so a tremolo or filter sweep repeats four times per second.
- Gate and sidechain timing. Match the attack and release of a gate to a note value to chop pads or bass into rhythmic stabs.
- Sample and loop length. Eight bars at 128 BPM last 15 seconds, so a 15-second loop in a hardware sampler will line up.
- Hardware without tempo sync. Guitar pedals, rack delays and modular modules usually have a time knob or a ms display.
Video editors can use the same maths. Cutting on the beat is easier when you know how many frames fit in each beat.
| Frame rate | ms per frame | Frames per beat at 120 BPM |
|---|---|---|
| 24 fps | 41.67 | 12 |
| 25 fps | 40 | 12.5 |
| 30 fps | 33.33 | 15 |
| 60 fps | 16.67 | 30 |
At 24 fps and 120 BPM a beat is exactly 12 frames, so cuts every beat, every two beats or every bar land on whole frames. At 25 fps you get half frames, which means some cuts will be a frame early or late.
Convert milliseconds back to BPM
Sometimes you start from the time and want the tempo. Maybe you found a delay setting you like and want to know what BPM it matches, or you measured the gap between two kicks in a waveform. The converter on the page takes a millisecond value and returns the BPM. The formula is the same one turned around: BPM = 60000 / ms.
| Gap in ms | BPM if it is a quarter note | BPM if it is an eighth note |
|---|---|---|
| 600 | 100 | 200 |
| 500 | 120 | 240 |
| 468.75 | 128 | 256 |
| 400 | 150 | 300 |
| 375 | 160 | 320 |
The table shows the catch. A gap of 375 ms is 160 BPM as a quarter note, but it is also a dotted eighth at 120 BPM. Always ask which note value the gap represents. If a result looks twice as fast or half as slow as the music, halve or double it.
Finding the tempo first
The calculator needs a tempo. If you have the project file, you already know it. If you only have a finished track, there are three ways to find it. Press the tap pad in time with the music and the calculator averages your taps. Open the tap tempo page at /tap-bpm/ if you want a dedicated tap page. Or load the audio into the BPM finder at /bpm-finder/, which analyses the file in your browser and also gives you the key.
If you are working from a full mix and need the drums or vocals on their own, you can split vocals at /vocal-remover/ first. A drums stem has a cleaner beat for tapping along.
Tap for at least eight beats before you trust the figure, and keep tapping through a few bars. The first two or three taps are the least accurate. If your result shows 63.9 BPM, try rounding to 64 and listen against the track.
Frequently asked questions
How do I convert BPM to milliseconds?
Divide 60,000 by the BPM. The answer is the length of one beat in milliseconds. For example, 60,000 divided by 120 is 500 ms, and 60,000 divided by 128 is 468.75 ms. The calculator does this instantly and shows the result for every note value too.
What delay time should I use for 120 BPM?
At 120 BPM a straight 1/4 note is 500 ms, a straight 1/8 is 250 ms, a dotted 1/8 is 375 ms and a 1/8 triplet is 166.7 ms. A dotted 1/8 is the most common choice for guitars and synths, and a 1/4 works well for slow, spaced echoes.
What is a dotted note in milliseconds?
A dotted note lasts one and a half times as long as the plain note. Multiply the straight time by 1.5. At 120 BPM a straight 1/8 note is 250 ms, so the dotted 1/8 is 375 ms. The table in the calculator lists all the dotted values for your tempo.
How do triplet times work?
Three triplet notes fit in the time of two straight notes, so each triplet is two thirds of the straight value. A straight 1/4 note at 120 BPM is 500 ms, so the 1/4 triplet is 333.3 ms. Triplets give a rolling, swung feel.
What is the best reverb pre-delay for my tempo?
Many mixers start with a pre-delay of 1/64 or 1/32 of a whole note. At 120 BPM that is 31.3 ms and 62.5 ms. Shorter values keep the reverb tight and close, longer values separate the dry sound from the tail. Listen and adjust, because the right figure depends on the part.
How do I sync an LFO to the tempo without a sync button?
Use the Hz column. Divide 1000 by the note's millisecond value, or read the Hz figure straight from the table. At 120 BPM, a 1/8 note is 250 ms, which is 4 Hz. Set the LFO rate to 4 Hz and one full cycle will match one eighth note.
How long are 8 bars at my BPM?
Multiply the length of a beat by 32, since eight bars of 4/4 contain 32 beats, or use 1920 divided by the BPM in seconds. At 120 BPM, 8 bars take 16 seconds. At 128 BPM they take 15 seconds. The calculator shows this figure for any tempo you enter.
Does the calculator work for time signatures other than 4/4?
The per-beat and note-value figures work in any time signature, because they depend only on the tempo. The per-bar figure and the 8-bar length assume four beats per bar. For 3/4, multiply the beat time by three to get the bar length instead.
Is the BPM calculator free, and is anything uploaded?
It is free, with no sign-up and no limits. All the maths runs in your browser, so nothing you type or tap is sent to a server. It works on phones as well as desktops.