Key Finder
Song key finder: find the musical key of any song from an audio file or your microphone, with a confidence score. Runs in your browser; nothing is uploaded.
About the key finder
This listens to a song and works out its musical key — which notes it’s built from and which one it centers on — by building a profile of how much energy falls on each of the twelve pitch classes, then matching that profile against the patterns real major and minor keys tend to produce.
How to use it
- Choose Microphone to analyze whatever’s playing nearby, or Upload File for a track you already have.
- Give it a reasonable stretch of the song — a single sustained chord won’t give the detector much to work with.
- Check the confidence percentage alongside the result — low confidence usually means the audio didn’t give a clear-enough tonal picture.
Tips for a reliable result
- A fuller mix with clear harmonic instruments (guitar, piano, strings, bass) gives a stronger reading than a drum loop or an unaccompanied melody.
- Verses and choruses with full harmony work better than sparse intros or breakdowns.
- Try a different section of the same song if the first result comes back with low confidence.
FAQ
Why does it show two keys, like “D Major (rel. B minor)”?
Every major key shares the exact same notes as a minor key a minor third below it — its relative minor. A pitch-class profile alone genuinely can’t always distinguish between the two, so this always shows both rather than guessing at a false certainty. The lead name is this tool’s best call on which one the song actually centers on.
Is this a song key finder or a song pitch finder?
It’s a song key finder: it tells you the key a song is in (for example D Major or B minor), which is the note and scale the music is built around. If you were looking for a song pitch finder, the key is usually what you’re after; to check a single sung or played note, the Tuner shows the pitch of what it hears.
How accurate is this?
Key detection from audio alone is an estimate, not a lookup, and it does better on some music than others — a full, harmonically clear mix is much easier to read than a sparse or percussion-heavy one. The confidence score is there for a reason: treat a low one as “unclear” rather than “wrong,” and double-check by ear or against a known source if you need certainty.
Does my audio get uploaded anywhere?
No — analysis runs entirely in your browser. See the Privacy Policy for details.
Is this the same tool as BPM Finder?
Yes — BPM Finder and this page share one analysis engine and run on the same audio; each just leads with a different result.