🎨 Seedream 5.0 Pro — ByteDance's flagship image model: up to 2K, best-in-class typography & multi-reference editing!

Try It!
Logo

Song Key Finder

Analyse up to 100 tracks in one run and get the key three ways — the musical name, the Camelot code and the Open Key number — then write it straight into the MP3 tag in whichever of the three your rig expects. The runner-up reading and the twelve pitch classes stay on screen, so you can see what the answer was built from.

Your track is analysed on this device — nothing is uploaded.

Drop your audio files here

or click to choose tracks — a whole folder can be dropped too

MP3, WAV, M4A, AAC, OGG, FLAC · up to 200 MB each · up to 100 tracks per run

Key detection is usually right, and when it is wrong it is almost always a fifth away or the relative major or minor — which is exactly why the runner-up sits next to the answer. Atonal music, heavy processing and percussion-only tracks have no key to find.

How it works: a spectral-flux onset envelope and autocorrelation give the tempo; a chromagram matched against the Krumhansl–Schmuckler key profiles gives the key. Both run in this tab.

How to Find and Tag the Key of Your Tracks

Three steps, all inside your browser

  1. 01

    Load a folder or up to 100 files

    MP3, WAV, M4A, OGG or FLAC up to 200 MB each. A dropped folder is searched for you, and the files are read from disk without ever leaving the tab.

  2. 02

    Read the key three ways

    The musical name, the Camelot code for harmonic mixing and the Open Key number, plus the relative key, the runner-up and how far the recording sits from A=440.

  3. 03

    Write it into the MP3 tag

    Choose whether TKEY should hold Am, 8A or 1m, then download the tagged files one by one or as a single zip. Only the tag changes; the audio is copied as-is.

Free Audio Tools

Free Tools

Frequently Asked Questions

Yes — that is what it is built for. Drop a folder or up to 100 files, and they are analysed one after another with a running count and a time estimate you can pause or stop. Every MP3 that comes back with a key can then be downloaded with that key written into its tag, one file at a time or as a single zip.
The ID3 specification defines TKEY as the musical key, at most three characters: Am, F#m, Eb, C. That is the default and the safest choice. Plenty of libraries and workflows are built around the Camelot wheel or Open Key instead and expect 8A or 1m in that same field, so both are offered — pick whichever your own software is already showing you.
No. The tag block at the front of the file is rebuilt, every other frame in it — title, artist, artwork — is copied byte for byte, and the audio and any ID3v1 trailer are carried across unchanged. If you want to check rather than take our word for it: the duration stays identical, and hashing only the decoded audio, for instance with ffmpeg -i track.mp3 -f md5 -, gives the same result before and after.
Those files are analysed exactly like MP3s — key detection does not care about the container — but their metadata lives in entirely different structures: Vorbis comments in FLAC and Ogg, atoms in MP4, RIFF chunks in WAV. Writing all of them properly is a separate job, and a partly-correct writer is worse than none at all, so for now the write-back is MP3 only.
Free, with no signup and no daily quota: the analysis runs on your own processor, so there is no server bill to pass on. It works in any modern mobile browser too — a few seconds per track — though a phone has less memory than a laptop, so a queue of very large lossless files is where an older device will struggle.
On our own synthetic test set — four-chord progressions written in C major, A minor, F# minor and E flat major, generated inside the unit tests and also run detuned by up to 45 cents — all of them come back correct. Real recordings are harder. When the tool is wrong it is almost always wrong in one of two specific ways: a fifth away, or the relative major or minor. That is precisely why the runner-up is printed next to the answer.
Camelot is the wheel DJ software uses for harmonic mixing: 8A is A minor, 8B is C major, and the two tracks that mix cleanly with either are the neighbours on the wheel and the same number in the other letter. If you are writing a song rather than mixing one, ignore it and read the musical name. Open Key is the same wheel rotated so that A minor is 1m.
Because a major key and its relative minor contain exactly the same seven notes — C major and A minor are built from an identical scale — so they can only be told apart by which note the music leans on. That judgement is the one this kind of analysis gets wrong most often, and seeing both makes the mistake easy to catch.
It is how far the recording sits from standard concert pitch, measured from the spectrum. Older records, tape, a piano that has drifted and anything pitched up for radio all land off 440, and a fifty-cent error would turn every note into its neighbour. The offset is measured first and the analysis shifted to match, so a slightly sharp track still gets the right key.
MP3, WAV, M4A, AAC, OGG, Opus and FLAC, plus the audio inside an MP4 or WebM. A lossless file is not required: key detection reads harmonic content, and a 192 kbps MP3 carries more than enough of it.
Never. The file is read from disk and decoded by the browser's audio engine; no request carries it anywhere. Open DevTools, go to the Network panel and run an analysis if you want to see that for yourself — or simply disconnect from the internet once the page has loaded.

AI Pricing Plans

Flexible AI Pricing

Pay-as-you-go credits or subscription plans. No hidden fees, cancel anytime.

One Time supports crypto payment (BTC, USDT, ETH, 350+) · Monthly billing

Free

Try before you buy

Free
32points
  • Up to 3 videos
  • Up to 32 images
  • Multi-Model Support
  • Text to Video
  • Image to Video
  • Video to Video
Show more (+11)
  • Consistent Character
  • AI Animation Generator
  • Templates & Effects
  • AI Video Enhancers
  • Interactive Community
  • Faster Generation Speed
  • No-watermark Outputs
  • More Camera Movement
  • Private Video Visibility
  • Copy Protection
  • Priority Support

Pro

Popular

Elevate your AI experience

29.99USD / 1 Month
800
800 credits/mo
  • Up to 80 videos
  • Up to 800 images
  • 3 tasks(Parallel Tasks)
  • Multi-Model Support
  • Text to Video
  • Image to Video
Show more (+12)
  • Video to Video
  • Consistent Character
  • AI Animation Generator
  • Templates & Effects
  • AI Video Enhancers
  • Interactive Community
  • Faster Generation Speed
  • No-watermark Outputs
  • More Camera Movement
  • Private Video Visibility
  • Copy Protection
  • Priority Support

Lite

Start your AI journey

19.99USD / 1 Month
300 credits/mo
  • Up to 30 videos
  • Up to 300 images
  • 3 tasks(Parallel Tasks)
  • Multi-Model Support
  • Text to Video
  • Image to Video
Show more (+12)
  • Video to Video
  • Consistent Character
  • AI Animation Generator
  • Templates & Effects
  • AI Video Enhancers
  • Interactive Community
  • Faster Generation Speed
  • No-watermark Outputs
  • More Camera Movement
  • Private Video Visibility
  • Copy Protection
  • Priority Support
  • Card
  • Crypto accepted (BTC, USDT, ETH, 350+)
View Detailed Pricing

Privacy preferences

We use essential storage to run the service. Optional analytics, advertising and convenience features stay off until you choose to enable them. Privacy policy