Free Song Key Finder with Camelot Codes

What the key of a song tells you

A song’s key is its home note plus a scale, either major or minor. In A minor, the music keeps returning to A and draws most of its notes from the A minor scale. With 12 possible home notes and two scale types, there are 24 keys.

Major keys tend to sound bright and settled, and minor keys darker or more tense, though tempo, sound and lyrics change the mood as much as the key does. The key also tells a player which notes and chords will fit when they join in.

The finder writes the key both ways: as a name, such as A minor, and as a Camelot code, such as 8A. The Camelot system numbers the keys 1 to 12 and adds A for minor and B for major, so DJs can see at a glance which tracks are compatible.

Some keys have two spellings. G♯ minor and A♭ minor are the same key, as are F♯ major and G♭ major, so a DJ app and a key finder can print different names for one key. The Camelot code is the same either way: G♯ minor and A♭ minor are both 1A.

How the key finder reads the key

The analyzer builds a chromagram of the whole track, a running measure of how much of each of the 12 pitch classes (C, C♯, D and so on, in any octave) is sounding. Adding it up over the song gives a profile of which notes the music leans on most.

That profile is then matched against Krumhansl key profiles, reference patterns from music psychology research that describe how strongly each note belongs to each of the 24 keys. In C major, for example, C, G and E weigh most and C♯ least. The closest match is the key, and the finder reports how confident that match is.

Because it looks at the whole track, a song that modulates, moving to a new key partway through, gets the key that dominates. A pop song that lifts its last chorus by a semitone usually reports the key of its verses and earlier choruses.

Why a song can read as its relative major or minor

Every major key shares all seven notes with one minor key, its relative minor. C major and A minor use the same white keys on a piano. The only difference is which note feels like home, so the two note profiles are close and a finder can hesitate between them.

The result shows the relative key for that reason. To decide between them, listen to the end of the chorus or the final chord. If it settles on C, the song is in C major. If it settles on A, it is in A minor. For mixing it matters little, since relative keys share a Camelot number and blend well.

Major keys, relative minors and key signatures

The table lists all 12 pairs in circle-of-fifths order. Each row adds one sharp or removes one flat compared with the row above, which is why neighboring Camelot numbers differ by a single note.

The relative minor always starts three semitones below its major key. Count down three piano keys from the major key’s home note, black keys included, to find it.

Finding the key by ear

A key finder is fast, and your ear can confirm its answer in four steps.

1. Play the song and hum the note where a phrase comes to rest, usually the last note of the chorus. That is the likely home note.
2. Find that note on a keyboard or a guitar. You can also play reference pitches with the tone generator and slide until one matches your hum.
3. Play a major scale and a minor scale from that note while the song runs. The one that fits without sour notes gives the mode.
4. Check the chords. If the song keeps using the chords from one row of the table below, that row is the key.

Chords that belong to a key

Each major key has seven chords built from its own notes, numbered with Roman numerals. Most pop and rock songs use three or four of them.

The relative minor uses the same chords, counted from the vi chord. A minor uses Am, B°, C, Dm, Em, F and G. Songs in minor keys often swap the minor chord on the fifth note for a major one, E instead of Em in A minor, and that major chord is a strong sign the song is in the minor key.

Harmonic mixing with the result

Harmonic mixing means playing tracks whose keys share most of their notes, so the overlap sounds like one piece of music. Under the result, the finder lists the keys that mix with the one it found: the same code, one step up or down on the same ring, the A/B partner and two steps up for an energy boost. The Camelot wheel shows every move from any of the 24 keys and how many notes each one changes.

Planning a set by key

A set that steps one number at a time around the wheel changes key gently, one note per mix, and can keep going for hours. Switching between A and B on the same number changes the mood without changing the notes, as a minor track hands over to its major partner.

Save the +2 move for the moment you want a lift, such as the start of a peak hour, since a whole-step rise is easy to hear. When two tracks you want back to back clash in key, keep the overlap short or cut between them on a phrase.

Key, tempo and pitch in a DJ mix

Changing a track’s speed changes its pitch unless key lock is on. A speed change of about 5.9% moves the music by a semitone, which is seven steps on the Camelot wheel, so an 8A track pitched up 6% plays closer to 3A. Check the tempo of each track with the BPM finder before you count on its key.

Mixxx, a free DJ app, detects the key and BPM of a whole library and has key lock, so a track can match another’s tempo without leaving its key.

Transposing to fit a voice or an instrument

Once you know the key, you can move a song to a better one. Each semitone up or down shifts every note by the same amount, so a song in G major moved down two semitones is in F major.

• Singers lower a backing track when the chorus sits too high, or raise it when the verses fall below their range. One or two semitones is often enough.
• Guitarists use a capo to play the same chord shapes in a higher key. Capo on fret 2 with G shapes sounds in A major.
• Producers pitch a loop or sample to the key of the beat before stacking it with other parts.

Audacity can shift the key of a recording without changing its speed, as covered in how to change speed, tempo and pitch in Audacity. Pitch correction needs the key as well, since the plugin snaps notes to that scale, as shown in how to autotune in Audacity.

When the key reading seems off

A key is a reading of the music, and some songs leave room for more than one answer. These are the usual reasons a result surprises you.

• It names the relative key. C major and A minor share their notes. Listen for where the chorus resolves and trust that note.
• The song changes key. The finder reports the key that dominates. Songs that move between two keys can show a lower confidence.
• The song uses a mode. Music in Dorian or Mixolydian, common in funk, folk and rock, gets matched to the nearest major or minor key, often one with the same notes and a different home note.
• The recording is off standard tuning. A song tuned away from A = 440 Hz, or an old record transferred at a slightly wrong speed, falls between two keys, and the result can land on either.
• Drums dominate the mix. Tracks with few sustained notes give the chromagram less to work with, so the confidence is lower. Check the result by ear against the bass line.
• Key tags in your library disagree. DJ apps and stores write key tags from their own analyzers and in their own notation: names with sharps or flats, Camelot codes, or Open Key codes, where 1d is C major. Compare the actual keys before assuming one tag is wrong.
• It is an edit of the original. A sped-up or slowed version changes key with its speed. A nightcore edit at 125% speed sits almost four semitones above the original.