Half-diminished Seventh Chords

What is a half-diminished seventh chord?

A half-diminished seventh chord is a four-note chord, which consists of four notes: the root, the minor third, the diminished fifth, and the minor seventh.

Half-diminished Seventh Chord Formula: 1-b3-b5-b7

The formula 1-b3-b5-b7 represents the intervallic structure of a half-diminished seventh chord:

• 1: The root note of the chord.
• b3: The minor third, which is three semitones above the root.
• b5: The diminished fifth, which is six semitones above the root.
• b7: The minor seventh, which is ten semitones above the root.

For example, in a C half-diminished seventh chord:

• Root note (1): C
• Minor third (b3): Eb
• Diminished fifth (b5): Gb
• Minor seventh (b7): Bb

The combination of these four notes (C, Eb, Gb, Bb) creates the sound of a C half-diminished seventh chord.

Characteristics of Half-diminished Seventh Chords

Half-diminished seventh chords have a unique and somewhat dissonant quality due to the diminished fifth and the minor seventh intervals. They are often used for creating tension and adding color to compositions.

Playing Half-diminished Seventh Chords

On a piano or keyboard, half-diminished seventh chords are typically played by pressing the root note, the minor third, the diminished fifth, and the minor seventh.

In guitar playing, half-diminished seventh chords are formed by pressing down specific combinations of strings and frets, following chord diagrams or finger positions.

List of half-diminished seventh chords for all keys

• Cm7b5 (or C half-diminished)

  

• C#m7b5 (or C# half-diminished or Dbm7b5)

  

• Dm7b5 (or D half-diminished)

  

• D#m7b5 (or D# half-diminished or Ebm7b5)

  

• Em7b5 (or E half-diminished)

  

• Fm7b5 (or F half-diminished)

  

• F#m7b5 (or F# half-diminished or Gbm7b5)

  

• Gm7b5 (or G half-diminished)

  

• G#m7b5 (or G# half-diminished or Abm7b5)

  

• Am7b5 (or A half-diminished)

  

• A#m7b5 (or A# half-diminished or Bbm7b5)

  

• Bm7b5 (or B half-diminished)