Audio Key Finder — Detect The Key Of Any Song In Your Browser
Drop any audio file and instantly discover its musical key — major or minor, with confidence scores for every candidate. The Audio Key Finder on Cuty.ai runs 100% in your browser using FFT-based chroma analysis and the Krumhansl–Schmuckler algorithm.
Drop an audio file here or click to browse
MP3, WAV, FLAC, OGG, M4A, WebM
Key features
Discover what makes this tool powerful — and private.
Accurate Key Detection With Chroma + Krumhansl–Schmuckler
We compute a full chroma vector with overlapping FFT windows, then correlate it against all 24 Krumhansl–Schmuckler key profiles. The detector reports the winning key plus a ranked table of every major/minor candidate so you can double-check relative keys yourself.
100% Private — Audio Never Leaves Your Device
The whole pipeline runs in the browser via the Web Audio API. Your audio is decoded locally, analysed locally, and discarded when you leave the page. No uploads, no accounts, no cloud queue.
Works With Every Common Format
MP3, WAV, FLAC, OGG, M4A / AAC, WebM — anything your browser can decode. Drag and drop a full track, a stem, a loop, or a rehearsal recording and get the key in a few seconds.
Pair It With Our AI Music Tools
Once you know the key, jump straight into the AI Backing Track Generator, the Chord Progression Builder, or the AI Remixer on Cuty.ai to create a new arrangement in exactly the same key.
Frequently asked questions
Everything you need to know about this tool.
It decodes your audio with the browser's Web Audio API, computes a chroma vector (a 12-bin summary of how much energy is present at each pitch class), then correlates that vector against the 24 Krumhansl–Schmuckler tone profiles — one for each major and minor key. The winning key is the one with the highest Pearson correlation.
No. The analysis runs entirely inside your browser tab. No file is ever transmitted to Cuty.ai or to any third party.
C major and A minor share the same seven notes, so a statistical detector can confuse them on short or tonally ambiguous clips. The confidence table below the result shows how close the runner-up is — if the two top candidates are relative keys within a few percent, the track may genuinely be modal or ambiguous.
Any format your browser can decode: MP3, WAV, FLAC, OGG Vorbis / Opus, M4A / AAC, and WebM. Files up to a few hundred megabytes work, though shorter clips (30 seconds – 5 minutes) are fastest.
Yes. The Audio Key Finder is a free utility — keys themselves aren't copyrightable, so you're free to use the information in covers, DJ sets, mashups, and original productions.
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