- Drop in an audio file or click to choose one — MP3, WAV, M4A, OGG, or FLAC. It stays on your device and is never uploaded.
- Wait a moment while it analyzes the notes in the track and reports the most likely musical key, with a confidence rating.
- Press “Hear chord” to play the home (tonic) chord of the detected key as a reference tone.
- Play the song and listen with the chord in mind — if it sounds resolved and at rest, the key is right.
- If it feels off, tap one of the other likely keys (often the relative major/minor) and compare by ear.
- Copy the key, then use the Scale Visualizer, Chord Progression Generator, or Capo Calculator to play along in that key.
About This Online Song Key Finder
Guitar Tool Hub's free song key finder (also called a key detector, key analyzer, or 'what key is this song in' tool) figures out the musical key of any song or audio file right in your browser. Drop in an MP3, WAV, M4A, OGG, or FLAC and it analyzes which of the 12 notes the music actually contains, then matches that fingerprint against all 24 major and minor keys to find the best fit — complete with a confidence rating and the most likely alternatives. Press play to hear the home chord and confirm the key by ear. Because all analysis happens locally on your device, nothing is ever uploaded — and it works best on pitched music with clear chords or melody.
- 01Detects the key of any uploaded audio file
- 02Scores all 24 major and minor keys
- 03Works with MP3, WAV, M4A, OGG & FLAC
- 04Confidence rating for each reading
- 05Shows the relative major/minor and other likely keys
- 06Visual note-content chart (chromagram)
- 07Play the tonic chord to confirm the key by ear
- 08Copy the detected key in one tap
- 09Runs entirely on your device — files never leave your browser
- 10Free — no account or install needed
Frequently Asked Questions
Upload the song (or any audio file) to the key finder and it analyzes which notes the music contains, then matches that against all 24 major and minor keys to report the most likely one — automatically. Once it shows a result, press the chord button to hear the home chord of that key and confirm it fits the song by ear.
For pitched music with clear harmony — chords, a strong melody, or vocals — detection is usually right or lands on the relative key (which shares the same notes). Each result comes with a confidence rating and a list of the next most likely keys. Tracks that change key partway through, modal music, or audio that's mostly drums and noise are harder and may need you to confirm by ear.
A major key and its relative minor (for example C major and A minor) use exactly the same seven notes, so their note content is identical — only the tonal center differs. When a song doesn't strongly emphasize its home note, the detector can land on the relative key. That's why the result shows the relative key and other likely options: play the home chord of each and pick the one your ear agrees with.
The Song Key Finder listens to audio — you upload a recording and it detects the key from the sound. The Key Finder works from text — you type or paste a chord progression and it works out the key from the chord names. Use this tool when you have a recording, and the Key Finder when you already know the chords.
No. The file is decoded and analyzed entirely in your browser using the Web Audio API. Nothing is sent anywhere, so it stays private and works even on large files without an upload wait.
You can load MP3, WAV, M4A, OGG, FLAC, and most common audio files your browser can decode.
It reports a single best-fit key for the section it analyzes (the first couple of minutes). If a song modulates, the result reflects the most prevalent key overall. For a specific section, trim the file to that part before uploading.
Yes — completely free. No account, no download to install, and no payment required. It runs entirely in your browser.