BPM Finder & Tap Tempo
The tempo of a song from its audio or your taps, with delay and reverb times.
Try before you buy.
- Free preview: how sure the reading is, playback with beat clicks and the first half of each table and reading, with the tempo of your song or taps and every time hidden.
- Locked until you unlock it: copy.
- Unlock: Pro pass, ₹179 for 30 days or ₹79 for 1 week, a one-time payment that never renews. Unlock: Pro pass, $5.99 for 30 days or $2.99 for 1 week, a one-time payment that never renews.
Ways to unlock shows how to get the full result.
Printing this result is locked in the free preview.
Tap along with the beat
Tap the button (or press Space, Enter or T) on every beat. Eight taps or more give a steady reading; a pause of 2.5 seconds starts again.
Waiting for taps
Tempo
Other ways to count it
Songs can be counted at half or double speed (and some with a triplet or dotted feel). Choose another tempo to use it for the clicks and the tables below.
Check it by ear
Plays the first minute of the song (at reduced quality) with a click on every beat of the chosen tempo. The bars above show where notes and drums start.
Type any tempo to use the tables as a delay calculator.
Delay times
| Note | Straight (ms) | Dotted (ms) | Triplet (ms) | Rate (Hz) |
|---|
Reverb that fits the tempo
| Size | Pre-delay (ms) | Decay (ms) | Total (ms) |
|---|
Pre-delay of a 64th note; the decay ends the tail on the note value.
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About the BPM Finder & Tap Tempo
Find the tempo of a song in beats per minute. Choose an audio file — MP3, WAV, M4A, FLAC, OGG, Opus — or a video, and the page listens for where drum hits and notes start, finds the beat that repeats through the song and fits a beat grid to it, so the result is precise to a fraction of a BPM on music with a steady beat. It also offers the half-time and double-time readings (a song at 70 BPM can just as well be counted at 140), says how sure it is and whether the tempo stays steady, and plays the first minute back with a click on every beat, so you can hear that it fits.
No file at hand? Use Tap tempo: tap along on the button, the Space bar or the T key, and the tempo appears after two taps and settles as you go on. Either way the page lists delay times for every note value — straight, dotted and triplet, in milliseconds and hertz — and reverb times that end on the beat. Everything runs in your browser; your music is never uploaded.
How to use it
- Under From a song, drop an audio file or a video on the box, or press Choose a song. The first 10 minutes are analysed, which takes a few seconds.
- Read the tempo at the top. If the song feels twice as fast or slow, choose the half-time or double-time reading under Other ways to count it.
- Press Play with beat clicks to hear the first minute with a click on every beat: the clicks should land on the drums.
- Or switch to Tap tempo and tap the button (or press Space, Enter or T) on every beat; eight taps or more give a steady reading.
- Use the Delay times and Reverb tables for your effects, or type any tempo to use them as a calculator. Copy results puts everything on the clipboard with a pass, or after unlocking this result; without one the free preview shows how sure the reading is and the first half of each table, with the tempo and every time hidden.
Examples
track.mp3 (128 BPM house)
128.0 BPM · High confidence · steady · half time 64.0 BPM
ballad.m4a (written at 72 BPM)
May read 144.0 BPM, with 72.0 BPM offered as half time: choose it to count the song as written
Both are the same beat; which one is “the” tempo depends on how you count it.
128 BPM
Quarter note 468.75 ms · dotted eighth 351.56 ms · eighth-note triplet 156.25 ms
120 BPM, short room (a quarter note)
Pre-delay 31.25 ms (a 64th note), decay 468.75 ms, 500 ms in total
Common uses
- Setting the project tempo of a remix or a mash-up.
- Matching songs for a DJ set or a workout playlist by tempo.
- Choosing delay and reverb times that sit in the groove.
- Finding the tempo of a song for a dance routine or band practice.
- Checking the tempo a live band played at.
How the tempo is found
- The sound is turned into an onset strength: in 20 frequency bands from 30 Hz to 5 kHz, how much louder each band gets from one 12-millisecond step to the next. It peaks where a drum is hit or a note starts.
- The page looks for the delay at which that pattern repeats best (its autocorrelation), in 8-second stretches across the song, and scores every tempo from 40 to 240 BPM — the beat period counts in full, two and three periods at half weight, and a gentle preference for tempos near 120 BPM settles a tie between a tempo and its double.
- A beat grid is fitted to the whole song around that tempo, which gives the result to a fraction of a BPM, and the first beat.
- Confidence is the share of 8-second stretches that find the same beat on their own; Through the song says how closely their tempos agree, or shows their range when they differ, so a live recording that speeds up shows a wider range.
Songs without a clear beat — ambient music, free-time singing, classical music with changing tempo — have no single BPM, and the confidence then reads Low.
Half time, double time and other readings
A beat can be counted at different levels: a drum-and-bass track is 174 BPM to a DJ and 87 BPM to someone nodding along with the snare, and a ballad with fast hi-hats can read 144 instead of 72. The page shows the reading it thinks most people would tap, and the others it found — half and double time, and where they are strong, a triplet or dotted feel (two thirds, three quarters …). Choose one to use it for the clicks and the tables; the beat grid is fitted again for it.
Delay and reverb times
One beat (a quarter note) lasts 60,000 ÷ BPM milliseconds: 500 ms at 120 BPM, 468.75 ms at 128 BPM. A note of n beats lasts n times that: a half note 2 beats, an eighth ½, a sixteenth ¼. Dotted notes are 1.5 times as long, triplets ⅔ as long. The rate column is 1000 ÷ the straight time in milliseconds, in hertz, for tempo-synced LFOs, tremolo and auto-pan.
The reverb table gives each size a pre-delay of a 64th note (31.25 ms at 120 BPM) and a decay of the note value minus the pre-delay, so the tail ends on the beat; treat them as starting points to adjust by ear.
Tips for tap tempo
Tap on the beat you feel most (often the kick and snare), for at least eight taps. The reading uses your last 16 taps, ignores one that is far off (a missed or doubled tap) and shows how evenly you tapped (± milliseconds). Stop for 2.5 seconds to start a new reading. Taps on a touch screen count when your finger touches it, which is more precise than when it lifts.
Limitations
- The tempo is found from the first 10 minutes; a DJ mix or a medley with several tempos shows the most common one, with a wide range under Through the song.
- Music without a steady beat has no single BPM, and some songs can fairly be counted in two or three ways; the page shows the readings it found.
- Playback with clicks covers the first minute, at reduced sound quality.
- Musical key detection is not part of this tool.
- The free preview shows how sure the reading is and the first half of each table and of the other readings, with the tempo and every time hidden; the rest, and Copy results, come with a pass.
Privacy
On this device; its files download once
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot. The audio engine (and, for some files, a WebAssembly decoder) downloads from MySmartCoPilot the first time you open a song. Your music is never uploaded. Tap tempo needs nothing.
Frequently asked questions
What do I get without a pass?
Without a pass, BPM Finder & Tap Tempo shows how sure the reading is, playback with beat clicks and the first half of each table and reading, with the tempo of your song or taps and every time hidden. Until you unlock it, the result can’t be copied. A Pro, Premium or Ultimate pass, a one-time payment that never renews, unlocks the full result. The pricing page lists the passes and their prices.
How accurate is the BPM?
On music with a steady beat the beat grid usually lands within a few hundredths of a BPM, so a track made at 128 BPM reads 128.0. Live recordings drift, and the result is then their average; the Through the song line shows how much the tempo moves.
Why does it say 140 when I count 70?
Both describe the same beat at different levels. The page picks the level most people would tap and shows the other one under Other ways to count it — choose it, and the clicks and tables follow.
How do I convert BPM to milliseconds?
Divide 60,000 by the BPM for one beat: 60,000 ÷ 128 = 468.75 ms. Multiply by 2 for a half note, by 0.5 for an eighth, by 1.5 for a dotted note and by ⅔ for a triplet. The Delay times table does this for every note value.
Does tap tempo work on a phone?
Yes. Tap the round button; the tap counts when your finger touches the screen. With a keyboard, press Space, Enter or T.
Is my song uploaded?
No. The file is decoded and analysed in your browser on your device and never leaves it.
Open-source components
This page can load these open-source components, each only when a task needs it:
- It uses FFmpeg under the LGPLv2.1 and the LAME MP3 encoder under the LGPL, through libav.js: licence and source code.
- It uses FFmpeg under the LGPLv2.1, through the Mediabunny add-ons: licence and source code.
- It uses the LAME MP3 encoder under the LGPL, through the Mediabunny MP3 add-on: licence and source code.
- It uses Mediabunny under the MPL 2.0: licence and source code.
You may replace them with your own builds. Their licences and the credits of every library the site uses are on the open-source credits page.