Free Tool
Song Key Finder
Drop in a track and get its musical key (major or minor) in seconds. Everything runs in your browser - nothing is uploaded.
Drop an audio file or click to upload
WAV, MP3, FLAC, M4A - analyzed in your browser, nothing uploaded
How to find the key of a song
Upload any audio file and the tool measures how much energy sits on each pitch class across the whole track, then matches that fingerprint against all 24 major and minor keys. It shows the best match plus the runner-up, which is often the relative key (for example A minor vs C major share the same notes).
Why the key matters
- Harmonic mixing: blend tracks in the same or neighbouring keys so they don't clash.
- Sampling & melodies: pick loops, one-shots and melodies that sit in key with your beat.
- Remixes & mashups: match acapellas and instrumentals in compatible keys.
When the track's done, master it with Sauce, or check the tempo with the BPM finder.
FAQ
How does the key finder work?
It builds a chromagram (how much energy sits on each of the 12 pitch classes) and matches it against the 24 major and minor key profiles to find the best fit - all in your browser. Nothing is uploaded.
How accurate is it?
It's a reliable estimate on tonal, harmonically-clear music. Because relative major and minor keys share the same notes, the runner-up is often the relative key - trust your ear against the root note. Percussive, atonal, or key-changing tracks are harder to pin down.
Is my audio file uploaded anywhere?
No. The key finder decodes and analyzes the file locally with the Web Audio API - it never leaves your device.
Why does knowing the key matter?
For harmonic mixing (blending tracks in compatible keys), picking samples, loops and melodies that sit in key, and choosing which songs to mash up or remix without clashing.