A Half-diminished
Am7b5
Notes
A · C · Eb · G
Intervals
- RootA (1P)
- Minor 3rdC (3m)
- Diminished 5thEb (5d)
- Minor 7thG (7m)
Fretboard
Adjust labels, frets, and palette in the interactive view.
About
The A half-diminished (A–C–E♭–G), also written Aø7, is the naturally occurring chord on the seventh degree of a major scale and on the second degree of a natural minor scale. Its primary role in jazz is as the ii chord in a minor ii–V–i: Am7♭5 → D7 → Gm. The E♭ is the defining color tone — without it, the chord collapses to a plain Am7. The 3rd and ♭7 together establish the minor seventh quality. On guitar, the fifth is essential and should not be omitted, since the ♭5 is precisely what distinguishes this chord. Compared to Adim7, m7♭5 is more grounded due to the natural (rather than doubly-flatted) seventh, giving it a somber but less frantic character.
Similar chords
Chords sharing two or more notes with this one, ranked by overlap.
Scales containing this chord
- A Blues (deg 1)
- B♭ Diminished (deg 8)
- B♭ Major (VII)
- B♭ Melodic Minor (VII)
- C Melodic Minor (VI)
- E Diminished (deg 4)
- E Harmonic Minor (IV)
- G Diminished (deg 2)
- G Harmonic Minor (II)
- G Natural Minor (II)
- A Locrian (I)
- C Dorian (VI)
- D Phrygian (V)
- E♭ Lydian (IV)
- F Mixolydian (III)
Scales whose notes include every chord tone. Roman numeral marks the chord root’s position in the scale; dashed badges aren’t linked yet.