Song Key Finder
Find the key and scale of any song. Drop in an audio file or an MP4 video, or let it listen to YouTube, Spotify or your microphone. You get the key, the scale notes, the chords in the key and the BPM.
Play a song from any speaker, YouTube, Spotify or the radio, and let FreeBPMFinder listen. You’ll get a first reading in about 6 seconds, and it gets more accurate the longer it listens.
Browser tab mode (Chrome and Edge on desktop) hears YouTube or Spotify directly. Pick the tab and switch on “Share tab audio”.
Listening for 0 s
Tempo
- Key, scale and BPM together
- Audio or MP4 video
- Never uploaded
- No app, no account
How the key finder works
The key finder decodes your audio or video file in the browser and measures how strongly each of the 12 notes sounds through the whole track, a profile called a chromagram. It also detects the chords as they change. It then compares both with every major and minor key and picks the best fit. Chord detection matters because it stops the classic mistake of naming a key a fifth away from the real one.
The result shows the key, a confidence rating, the relative key, the Camelot code for DJs, the notes of the scale and the chords in the key. Musicians use the scale to improvise and write melodies, and the chord list to work out a song by ear.
Use it as a scale finder
Every key has a scale. A major key uses the major scale (C major: C D E F G A B), and a minor key uses the natural minor scale (A minor: A B C D E F G). Once the key finder names the key, it spells out the scale with the right sharps or flats, so you can solo over the track, harmonize a vocal line or check which notes are “safe” for a melody.
| Key | Scale notes | Chords in the key |
|---|---|---|
| C major | C D E F G A B | C Dm Em F G Am Bdim |
| G major | G A B C D E F♯ | G Am Bm C D Em F♯dim |
| D major | D E F♯ G A B C♯ | D Em F♯m G A Bm C♯dim |
| A minor | A B C D E F G | Am Bdim C Dm Em F G |
| E minor | E F♯ G A B C D | Em F♯dim G Am Bm C D |
Find the key of a video, YouTube or Spotify song
- Video file: choose an MP4 (or WebM) video in Upload audio or video. The soundtrack is read on your device.
- YouTube or Spotify: on desktop Chrome or Edge, choose Listen live › Listen to a browser tab and share the tab with audio.
- Phone: play the song from another speaker and use Listen with microphone.
Change the key or find a capo
Found the key but it’s too high or low to sing? Open the free chord transposer to move the chords to any key and see the easiest capo position on guitar, or look it up in the capo chart. Singers can check which key suits their voice with the what key should I sing in tool.
Key finder FAQ
How do I find the key of a song?
Drop the song into the key finder above, as an audio file (MP3, WAV, M4A) or an MP4 video, and you’ll get the key in a few seconds. You can also play the song near your microphone, or share a YouTube or Spotify tab on desktop Chrome or Edge. The result shows the key, its scale notes, the chords that belong to it and the relative major or minor.
What is a song key finder?
A song key finder listens to a piece of music and works out its musical key, such as C major or A minor. This one measures how much of each of the 12 notes is present, detects the chords, and compares them with all 24 major and minor keys. It also finds the BPM at the same time.
Can it find the scale of a song too?
Yes. Along with the key, the result lists the notes of the scale (for example A B C D E F G for A minor) and the seven chords built on it. That makes it a quick scale finder for improvising, writing a melody or working out a solo over a track.
Is the key finder free?
Yes. It’s completely free, with no sign-up, no app and no limit on the number of songs. Your files are analyzed in your browser and never uploaded.
Can I find the key of a video?
Yes. Choose an MP4 video, such as a screen recording or a phone video of a band, and the key finder reads its soundtrack. WebM videos work in most browsers too. If a video won’t open, save it as MP4 and try again.
Why does the key finder say C major when the song is in A minor?
C major and A minor use exactly the same seven notes, so they are called relative keys. The finder shows both. If the song sounds sad or dark, the minor key is usually right; if it sounds bright, pick the major.
What does the Camelot number mean?
Camelot codes (1A to 12B) are a DJ shorthand for keys. A is minor and B is major. Tracks with the same code, or one step away, mix together smoothly. The key finder shows the Camelot code for every result.
Can I change the key after I find it?
Yes. Click Transpose chords or find a capo under the result to open the chord transposer with the chords of that key ready to move up or down, plus the best capo position for guitar.