Song Key Finder

What a song's key tells you

The key names the note a piece of music feels anchored to and whether it uses a major or minor scale. A song in A minor keeps returning to A and mostly uses the notes A, B, C, D, E, F and G. Knowing the key helps singers pick a comfortable range, musicians jam or transpose without guessing, producers choose samples that sit well together, and DJs mix tracks whose harmony does not clash.

Major and minor keys come in pairs that share the same seven notes: C major and A minor, G major and E minor, and so on. They are called relative keys. A detector can tell them apart only by which notes are emphasised, so the runner-up shown under the result is often the relative key. That is a property of music, not a fault of the tool.

How the key finder works

The tool decodes up to two minutes from the middle of the track, where verses and choruses usually sit, and splits it into short overlapping windows. For each window it measures how much energy falls on each of the twelve note names, adding octaves together. This is called a chromagram. Before folding the notes, it checks whether the recording is tuned slightly sharp or flat of the usual A = 440 Hz, so an older or detuned recording is not smeared across two neighbouring notes.

The averaged note profile is then compared with the Krumhansl-Kessler key profiles, a well-known model from music psychology of how strongly each note of a scale is felt in major and minor keys. All 24 possible keys are scored, and the best match is reported with its runner-ups. Everything runs in your browser: the file is not uploaded.

Using the Camelot wheel for harmonic mixing

DJ software often shows keys as Camelot codes: a number from 1 to 12 and a letter, A for minor and B for major. Keys next to each other on the wheel mix smoothly. From 8A (A minor) you can move to 7A or 9A, to 8B (C major, the relative major), or stay on 8A. A jump of two or more numbers usually sounds tense unless the tracks are mostly drums.

For example, a track in 8A followed by one in 9A (E minor) shares six of its seven notes, so long blends stay consonant. The result panel shows the Camelot code next to the key name so you can tag your library the way your mixing software expects.

When the result can be wrong

Key detection is reliable for songs with clear chords and a stable tonal centre. It struggles with music that changes key, uses modes such as Dorian or Mixolydian, is mostly drums or speech, or is atonal or heavily distorted. A track that modulates up for the last chorus has two correct answers, and the middle-of-the-song passage decides which one you see.

When confidence is moderate, test it: hum or play the suggested root note over the song. If it sounds like home, the key is right. If the relative key fits better, use that one. For tempo, use the BPM finder and tap tempo; key and tempo together are what most DJ tags need.

Getting audio to analyse

Use files you own or have permission to process: your own recordings, purchased downloads, or stems from a project. If the music is in a YouTube video you have rights to, convert it to MP3 or Opus with the AudioFetcher converter first, then choose that file here. The analysis copy never leaves your device, and closing the tab clears it.