BPM & key finder
Drop an audio file and get its tempo and key in seconds. Free, no sign-up, and your file is deleted as soon as the analysis finishes.
Drop your audio file here
MP3, WAV, M4A, AAC, OGG or FLAC — 20 MB max
What the BPM of a beat is for
BPM (beats per minute) is the tempo of the track. It is the first thing a rapper or a buyer looks at, because it decides whether the beat fits their flow. On marketplaces like BeatStars it is also a search filter: a beat with no BPM filled in simply does not appear in filtered results.
Common ranges: modern trap often sits between 130 and 150 BPM (felt at half time, so around 65-75), UK drill between 138 and 145, boom bap between 85 and 95, afrobeat between 100 and 110. These are not rules but expectations — departing from them should be a choice, not an accident.
Why the key matters just as much
The key tells you the note and mode (major or minor) the track is built on. It serves two very concrete purposes: letting an artist know whether the beat sits in their range, and letting an engineer pick vocal harmonies that do not clash.
The mode also sets the emotional colour. Minor dominates trap and drill because it carries tension. A beat in major does not sell worse, but it speaks to a different register — better to own that than to stumble into it.
How the detection works
Tempo is estimated from the onset envelope of the track, whose autocorrelation reveals the dominant periodicity, then corrected for harmonic errors — that is what keeps a 140 BPM beat from being reported as 70 or 280. The key is determined by correlating the pitch class profile against the Krumhansl-Schmuckler profiles.
No automatic detection is infallible. Heavily syncopated tracks, tracks without clear drums, and tracks with shifting tempo remain hard. The confidence score tells you how clean the result is: below 70%, check by ear before publishing the value.
What happens to your file
Nothing. The file is received, analysed on its first 60 seconds, then deleted from the server — whether the analysis succeeded or failed. It is not stored, not listened to, not used for anything else. No account is needed and no personal data is requested.
FAQ
Is the BPM finder really free?
Yes, and no sign-up is needed. The only limit is 5 analyses per hour per IP address, to keep the tool from being repurposed as a bulk analysis service.
Is my audio file kept?
No. It is deleted from the server as soon as the analysis ends, successful or not. No storage, no reuse.
Which formats are accepted?
MP3, WAV, M4A, AAC, OGG and FLAC, up to 20 MB. Only the first 60 seconds are analysed, which is enough for both tempo and key.
How reliable is the detection?
On a beat with clean drums, very reliable — and every result comes with a confidence score. Heavily syncopated or variable-tempo tracks remain hard to analyse automatically: below 70% confidence, verify by ear.
Why is the tempo double or half what I hear?
That is the classic half-time ambiguity: a trap beat felt at 70 is usually written at 140. The detection corrects these harmonic errors, but the convention it reports is the written tempo — the one you put in a beat title.