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

DegreeNoteFrequency (A=440, Equal)
1 A 440.000 Hz
♭3 C 261.626 Hz
♭5 D# 311.127 Hz
♭7 G 391.995 Hz

Chord Notation

Notation TypeSymbol / Value
Lead Sheet SymbolAø7
All Common Symbolsø7, m7♭5
Interval Formula1-♭3-♭5-♭7
Harmonic Categorydissonant

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

Inversions

InversionNotes (low to high)Bass NoteSlash Notation
Root Position A C D# G A A Half-Diminished Seventh (Minor 7♭5)
First Inversion C D# G A C A Half-Diminished Seventh (Minor 7♭5)/C
Second Inversion D# G A C D# A Half-Diminished Seventh (Minor 7♭5)/D#
Third Inversion G A C D# G A Half-Diminished Seventh (Minor 7♭5)/G

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.

Common Progressions

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

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:

Tuning Frequencies Across Temperaments

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

NoteEqual Temp.PythagoreanJust Intonation
A 440.000 Hz 440.000 Hz 436.043 Hz
C 261.626 Hz 260.740 Hz 261.626 Hz
D# 311.127 Hz 309.026 Hz 313.951 Hz
G 391.995 Hz 391.111 Hz 392.438 Hz

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: