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Find BPMFree online BPM and key analyser
BPM finder with key detection, to one decimal
Find BPM is a free BPM finder that reads a song's tempo and musical key in your browser, with no signup and nothing to install. Drop up to 20 files — MP3, WAV, FLAC, M4A, OGG or AIFF, 100 MB each — and every one comes back with its BPM to one decimal place, its key and Camelot code, and a beat grid you can play along to.
A track takes about a second. Half-time and double-time readings are one click away, and the whole batch exports as a CSV.
- 100% free
- No signup
- BPM + key + Camelot
- 20 files per batch
- CSV export
Drop a song here to read its tempo
MP3, WAV, FLAC, M4A, OGG, AIFF — 20 files per batch, 100 MB each
No track analysed yet
Add a file on the left and its BPM, key and beat grid appear here — usually in under a second.
How to find the BPM of a track
Three steps, about a second per track, nothing to install.
Add a track
Drag an audio file onto the drop zone, press “Pick audio files” to browse, or paste one with ⌘V / Ctrl+V. Up to 20 files of 100 MB each per batch; analysis starts the moment a file lands.
Read the tempo and the key
The BPM appears to one decimal place next to the key and its Camelot code. If a track reads half or double what you expected, the alternatives sit right below the number and switch with one click.
Check it, then copy it
Press “Play along” (or the space bar) and the four dots follow the detected beat grid — turn on the metronome click and a wrong reading drifts audibly within a bar. Click anywhere on the waveform to jump there; the bar lines drawn over it are the grid itself.
Take the numbers with you
Copy the results as text, download the batch as a CSV, or export every beat time in the grid as its own CSV for placing markers in an editor.
Technical specifications
| Supported input formats | MP3, WAV, FLAC, M4A, AAC, OGG, Opus, AIFF, WebM — whatever the browser decodes |
|---|---|
| What you get per track | BPM to one decimal, musical key, Camelot code, relative key, the three keys it mixes with, beat-clarity and key-match scores, first-beat offset |
| Tempo range | 40–240 BPM |
| Batch limit | 20 files per batch, 100 MB each |
| Analysis window | Up to 3 minutes, taken from the middle of a longer track |
| Checking the result | Waveform with bar lines, click-to-seek playback, metronome click on the detected grid |
| Export | Copy as text, a CSV of the batch, or a CSV of every beat time in the grid |
| Processing location | Your browser — Web Audio decoding plus a Web Worker, nothing uploaded |
| Price | Free — no signup, no daily limit |
| Works offline | Yes, once the page has loaded |
Frequently asked questions
- How do I find the BPM of a song?
- Drop the audio file on this page and the BPM appears in about a second. The analyser builds an onset envelope from the track, measures how that pattern repeats, and reports the tempo to one decimal place — no tapping along, no account, no software to install.
- Is this BPM finder free?
- Yes, entirely. There is no signup, no daily quota and no paid tier: the 20-file batches, the key detection, the CSV export and the beat-grid playback are all part of the free tool.
- How accurate is the BPM it finds?
- On a track with a steady beat it lands within a few hundredths of a BPM, which is why the figure is printed with a decimal at all — 128.0 and 127.6 are different tracks to a DJ. Live recordings, rubato playing and tracks that change tempo partway through are harder, and the beat-clarity score next to the result is there to say so: a low score means the analyser could not find one repeating pulse.
- Why does it show half or double the tempo I expected?
- Because both readings are musically true and the choice is a matter of feel — a drum-and-bass track at 174 BPM is also a valid 87 BPM, and hip-hop at 85 is often counted as 170. The analyser picks the reading a listener is most likely to tap, and lists the half-time and double-time alternatives underneath so you can switch with one click; the beat grid and the copied results follow whichever you pick.
- Can it find the key of a song as well as the BPM?
- Yes — every analysis returns the musical key, its Camelot code (the 1A-12B notation mixing software uses, where neighbouring numbers mix cleanly) and the relative major or minor. Key detection is the harder of the two jobs: it is reliable on material with clear harmony and less so on sparse or heavily processed tracks, so the runner-up key and a key-match score are shown next to it rather than hidden.
- Which audio formats can I analyse?
- MP3, WAV, FLAC, M4A, AAC, OGG, Opus, AIFF and WebM — anything your browser can decode. Chrome and Firefox read the whole list; Safari has no Ogg Vorbis support, and a file it cannot decode is reported as such instead of failing quietly.
- Can I find the BPM of a YouTube video or a Spotify track?
- Not from a link — the analyser reads audio files from your device, not URLs. Save or export the audio first (for a track you own, or from a video you are allowed to download) and drop the file here.
- What if I do not have the audio file?
- Then tap it: the tap tempo counter on this site turns your clicks or space-bar presses into a BPM, which is the only way to read the tempo of a live band, a rehearsal or a song playing across the room. It cannot tell you the key — that needs the audio itself — and it lands within a few tenths of a BPM rather than a few hundredths.
- Can I paste an audio file instead of picking one?
- Yes. Copy a track in Finder or File Explorer, then press ⌘V or Ctrl+V anywhere on this page and it joins the queue. Pasted files arrive without usable names, so each one is listed as pasted-1, pasted-2 and so on with the right extension.
About this tool
Find BPM exists because the two numbers a musician reaches for first — how fast a track is and what key it is in — are usually printed nowhere. DJs need them to beatmatch and to mix in key, producers need them to fit a sample to a project, and anyone learning a song by ear needs the tempo before they can slow it down.
The analysis has two halves. For tempo, the track is turned into an onset envelope — a curve of how much new energy arrives each instant, weighted towards the bass, since that is what listeners tap along to — and the repetition in that curve is measured to find the beat period, its phase, and the readings a listener might count instead. For key, the spectrum is folded into twelve pitch classes and matched against the Krumhansl-Schmuckler profiles, the listener ratings that tonal key estimation has been built on since 1982.
Both halves run on your own device: the browser decodes the audio with the Web Audio API, and the maths happens in a Web Worker so a long track never freezes the page. Want the key in the big type instead of the tempo? The key finder is the same engine, read the other way round.
Your tracks stay on your device
An unreleased mix is not something to hand to a stranger's server, so this tool never asks you to. Decoding and analysis both happen inside the browser tab, no audio or filename is transmitted anywhere, and the results exist only in the page until you copy or export them. Load the page once and you can put the laptop in airplane mode and keep analysing.