How to Find the Key of a Song

What does 'key' mean?

A key is a tonal center — one note that feels like home — plus the scale built on it. A song in C major uses mostly the notes of the C major scale (C D E F G A B) and sounds finished when it lands on a C major chord.

Keys are major or minor. Every major key has a relative minor that uses exactly the same seven notes: C major and A minor share them all, and so do G major and E minor. That is why knowing a song's notes isn't enough on its own — you also need to know which note feels like home.

Method 1: Detect the key from the audio

The fastest way is to upload an audio file of the song to the Song Key Finder. It analyzes which pitches are heard most throughout the recording and reports the most likely key with a confidence score, together with the relative key, the scale and chords of that key, and the other keys it considered. The BPM Finder reports the key too, alongside the tempo.

A high confidence score means one key clearly fits best. A low score means no single key clearly fits, which happens when a song changes key, borrows chords from outside its key, or sits between a major key and its relative minor. Key detectors' most common mistakes are naming the relative major or minor, or a key a fifth away, because those keys share most of their notes — so check doubtful results with the chords or by ear.

Method 2: Work out the key from the chords

If you know the chords — from a chord chart, a tab, or by working them out on your instrument — you can find the key in four steps.

1. Write down the chords of the song, or at least of a verse and chorus. If you're not sure what a chord is, pick its notes in the Chord Finder and it names it.
2. Find the key whose chords include them all. A major key's chords are I, ii, iii, IV, V, vi and vii°: in C major that's C, Dm, Em, F, G, Am and Bdim. The Chord Finder lists every key that contains a chord, and the Scale Finder shows the chords of any key.
3. Choose between the major key and its relative minor. The same chords fit both, so listen for the chord that feels like home — usually the one the song ends on and keeps returning to. C, F, G and Am fit both C major and A minor: if the song rests on C it is in C major; if it rests on Am it is in A minor.
4. Look for a major V chord. Minor-key songs often make their v chord major, so an E or E7 alongside A minor's chords points to A minor, even though E major isn't one of C major's chords.

Chords from outside the key don't always mean a different key. Songs borrow chords — a major-key song might use the minor iv chord, such as Fm in C major — so go by the chords that appear most and the chord the song resolves to.

Two more clues help. On sheet music, the key signature narrows it to one major key and its relative minor: one sharp means G major or E minor. On guitar, a capo raises the key one semitone per fret, so G-major shapes with a capo on the 2nd fret sound in A major.

Most songs reuse a handful of progressions, such as I–V–vi–IV. Common Chord Progressions shows them in Roman numerals, so you can recognize them in any key.

Method 3: Find the key by ear

1. Play the song and hum the note that feels most at rest — usually where the melody ends its phrases and where the song finishes.
2. Find that note on a piano, a guitar or a tuner app. Held while the song plays, the right note sounds settled; if it clashes, try the notes next to it.
3. Decide whether the home chord is major or minor. Major often sounds brighter and minor darker, but that is only a rough guide: the reliable test is to play both the major and the minor chord on your note along with the song and keep the one that fits.

Your home note plus major or minor is the key: a home note of A with a minor chord means the song is in A minor.

When a song isn't in one key

Key changes: many songs move up for the final chorus, or change key between sections. Find the key of each section separately. The Song Key Finder analyzes the whole recording and reports one key, so check each section from its chords or by ear.

Modes: some songs use a mode, such as Dorian or Mixolydian, which shares its notes with a major key but rests on a different note. A song in D Dorian uses the notes of C major but rests on D minor, so it is often described as D minor with a raised 6th.

No clear key: songs built on one or two chords, songs over a drone, and atonal music may not have a single clear key, so a detector's answer can be misleading.

Keys for DJs: Camelot notation

Many DJs write keys in Camelot notation, a wheel numbered 1 to 12 with A for minor keys and B for major keys. C major is 8B and A minor is 8A. Tracks with the same code, the same number with the other letter, or a number one step away with the same letter are compatible for harmonic mixing.

The Song Key Finder and BPM Finder name keys in standard notation, such as A minor; a Camelot chart converts them.