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Key

A♭ major

A♭ major is the major key with four flats in the key signature: B♭, E♭, A♭ and D♭. Its relative minor is F minor. On the circle of fifths it lies between E♭ major and D♭ major, the two neighbours that share six of their seven notes with it.

Tonic
A♭
Key signature
4 ♭ (on B, E, A and D)
Tonic chord
A♭–C–E♭
Relative key
F minor
Neighbours on the circle of fifths
E♭ major (3 ♭), D♭ major (5 ♭)

Four flats

The page Circle of Fifths shows the series of flat keys going anticlockwise: F major with one flat, B♭ major with two, E♭ major with three, A♭ major with four. The four flats are on B, E, A and D. The order of the flats is B♭ – E♭ – A♭ – D♭ – G♭ – C♭ – F♭, each a perfect fifth away from the one before.

A♭ major scale

A♭ B♭ C D♭ E♭ F G A♭ 1 1 ½ 1 1 1 ½

Here all the flats are written as accidentals before the notes: B♭, E♭, A♭ and D♭. The tonic A♭ and the fourth degree D♭ are marked; D♭ is the flat that was added last in the key signature. The pattern tone, tone, semitone, tone, tone, tone, semitone holds in every major key.

Recognising the key

The trick for flat keys: the tonic is the second-to-last flat. With four flats (B♭, E♭, A♭, D♭) the second-to-last is A♭, so the piece is in A♭ major. With it goes the relative minor F minor with the same key signature. It begins three semitones below the major key, as is the rule for all relative keys.

Chords

The seven diatonic chords arise as in every major key by stacking thirds. According to the page Diatonic chords the sequence of qualities major, minor, minor, major, major, minor, diminished holds in every major key; only the note names change.

DegreeChordNotesQuality
IA♭A♭–C–E♭major
iiB♭ minor (B♭m)B♭–D♭–Fminor
iiiCmC–E♭–Gminor
IVD♭D♭–F–A♭major
VE♭E♭–G–B♭major
viFmF–A♭–Cminor
vii°G°G–B♭–D♭diminished
A♭ID♭IVE♭VA♭I
Try it yourself: In the module Key Signatures you practise naming the key for a given key signature. At higher levels it also asks for the relative minor keys.

Continue on Maikstrings

Circle of fifths

All keys in a circle, with key signatures, relatives and diatonic chords.

Key Signatures

Quiz on key signatures and keys.

Diatonic chords

How the seven chords of every major key arise.

Related terms

F minorD♭ majorE♭ majorCircle of fifthsKeyRelative keyAccidentalDiatonic chord

Editor: Maik Krohm · reviewed on 3 October 2026

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