Three simple steps
How to find a song’s BPM and key
- 01
Choose an audio file or drop it into the analyzer. MP3, WAV and other formats supported by your browser can work.
- 02
Wait while your device decodes the file and estimates its tempo and musical key.
- 03
Read the BPM, major or minor key and key-match score. Check the result by listening before using it in a mix.
What do BPM and musical key tell you?
BPM stands for beats per minute: a track at 120 BPM has about two beats per second. Musical key describes its tonal center and mode, such as C major or A minor. Together they offer a useful starting point for choosing tracks that work well together.
How this analyzer works
The tempo detector compares changes in audio energy over a section of up to 75 seconds near the middle of the recording. The key detector samples frequency information across the track and compares its pitch-class profile with major and minor profiles. The key-match score describes profile similarity; it is not a calibrated probability that the key is correct.
When to double-check the result
Tempo changes, live drumming, quiet intros and complex rhythms can make automatic BPM detection uncertain. Half-time and double-time interpretations are common. Key changes, percussion-only recordings and ambiguous harmony can also affect key estimates. This tool reports one overall key rather than a timeline of changes.
A little more clarity
Frequently asked questions
Is the BPM and key finder free?
Yes. Both the BPM & Key Finder and LUFS Meter are free to use without creating an account.
Does my audio leave my device?
No. This analyzer decodes the file in your browser and runs its analysis in a local web worker. It does not upload the audio to a server.
Which audio file types can I use?
Use MP3, WAV or another audio format your browser can decode. M4A and other formats depend on the browser and codec. If a file cannot be decoded, try a WAV or MP3 version.
Why is the BPM half or double what I expected?
A rhythm can be interpreted at different beat levels. For example, 70 BPM and 140 BPM may both fit the same recording. Listen to the pulse and choose the value that matches your intended use.
Can I analyze a YouTube or Spotify link?
No. This version analyzes local audio files, not streaming links. Choose an audio file you have permission to use.
Built with open-source foundations
The analysis approach is adapted from Tonalux Analyzer. See our open-source acknowledgements. Results are estimates; limitations are described above.