A Half-Diminished Seventh (Minor 7♭5)

Chord Tones: A Half-Diminished Seventh (Minor 7♭5)

Symbol: ø7, m7♭5 — Formula: 1-♭3-♭5-♭7

Chord Notation

Roman numeral (e.g. I, IV, V) and Nashville Number notation are key-dependent. See Keys pages for chord function within specific keys.

Inversions

Harmonic Function

The A half diminished chord commonly functions as the submediant (vi) in C major or dominant (V) in D major. Its harmonic role varies by key — in major keys it provides stable harmonic grounding.

The half-diminished chord (minor seven flat five) combines a diminished triad with a minor seventh. It is the ii chord in minor keys and an essential sound in jazz and classical harmony. The A Half-Diminished Seventh (Minor 7♭5) specifically contains 4 notes: A, C, D♯, G (formula: 1-♭3-♭5-♭7). On guitar, A-rooted chords anchor to the open A string (5th string), and barre chord shapes rooted on A form the basis of the "A-shape" CAGED system. Blues, rock, and country music use A-rooted chords extensively — the classic 12-bar blues often starts on A, and many rock power chord riffs center on the open A string.

Common Progressions

The A Half-Diminished Seventh (Minor 7♭5) frequently appears in these progression patterns (shown in Roman numeral notation relative to key):

• iihd7-V7-i
• viihd7-I

Songs Featuring the Half-Diminished Seventh (Minor 7♭5)

Well-known songs where the A Half-Diminished Seventh (Minor 7♭5) — or this chord type — plays a prominent role:

• Autumn Leaves (minor ii chord) – jazz standard
• Beautiful Love – jazz standard
• Solar – Miles Davis

Tuning Frequencies Across Temperaments

Frequencies shown at A=440 Hz. View full temperament data for any note.

Scales Containing the A Half-Diminished Seventh (Minor 7♭5)

These scales include the A Half-Diminished Seventh (Minor 7♭5) as a diatonic or characteristic chord: