Upload a track and this free key and BPM finder detects its tempo and musical key automatically. The analysis runs entirely in your browser — your audio file is never uploaded anywhere.
Runs entirely in your browser. Your file is never uploaded anywhere.
How to find the key and BPM of a song
- Click the upload area, or drag an audio file straight onto it.
- The tool analyses the track right in your browser — nothing is sent to a server.
- Read the detected BPM and the estimated musical key.
Why knowing the key and BPM matters
The key tells you which notes and chords will sound in tune with a track, and the BPM tells you its tempo. Together they’re essential for DJing, remixing, mashups and sampling. If you want to layer an acappella over an instrumental, both need to be in a compatible key and at the same tempo, or the mix will clash. This song key finder gives you both numbers in seconds.
What you can do with the key and BPM
- Harmonic mixing — match songs in compatible keys for smooth DJ transitions.
- Remixing and mashups — line up acappellas and instrumentals that share a key and tempo.
- Sampling — pitch and time-stretch a sample to fit the key and BPM of your project.
- Covers and practice — find the key of a song so you can play or transpose it.
How accurate is automatic key and BPM detection?
BPM detection is usually very reliable for music with a clear, steady beat. Key detection is an estimate: it analyses the harmonic content of the track and picks the most likely key. It works best on clean, tonal music and can be less certain on busy, heavily processed or atonal tracks. Treat the key as a strong starting point, then confirm by ear.
Frequently asked questions
How do I find the key of a song?
Upload the audio file and this key finder analyses its harmonic content to estimate the musical key, along with the tempo in BPM.
Is my audio file uploaded anywhere?
No. The analysis runs entirely in your browser. Your file never leaves your device.
How accurate is the key detection?
Key detection is an estimate. It works well on clear, tonal music but can be less certain on very busy or atonal tracks.
What audio formats are supported?
Common formats such as MP3, WAV and M4A work in most modern browsers.
Can I find the BPM by tapping instead?
Yes — if you’d rather tap along to the beat, use our BPM Tapper.