semicord

Dm7b5 D half-diminished seventh chord

Notes
D F Ab C
Formula
1 b3 b5 b7
Semitones
0 3 6 10 above the root
Other symbols
Dø7, Dø, Dm7(b5), Dmin7b5

D to F is a minor third (3 semitones), F to Ab is a minor third (3 semitones), Ab to C is a major third (4 semitones). A diminished triad plus a minor seventh, C, so D to Ab is a tritone. It is also called half-diminished: the fully diminished Ddim7 has a diminished seventh (9 semitones) instead. With F in the bass the same four keys read as Fm6.

Dm7b5 on the piano

C4D4E4F4G4A4B4C5D5E5F5G5A5B5C#4Eb4F#4Ab4Bb4C#5Eb5F#5Ab5Bb5C4DFAbCC5

Root position from D4: D4, F4, Ab4, C5. Middle C is C4.

Dm7b5 on the guitar

Standard tuning (E A D G B E). Strings run low E on the left to high e on the right, frets downwards; × is a muted string, ○ an open string, and each dot shows the note it sounds, with the root in blue-green. Every shape below has D as its lowest note.

5fr×DDAbAbCCFF×
A-shape barre, root on the A string at fret 5
x 5 6 5 6 x (low E to high e)
Sounds D3 Ab3 C4 F4
9frDD×CCFFAbAb×
E-shape, root on the E string at fret 10
10 x 10 10 9 x (low E to high e)
Sounds D3 C4 F4 Ab4

The E-shape and A-shape grips are movable: an E-shape chord's root is the note under your first finger on the low E string, an A-shape chord's root is the note on the A string. Slide the same grip up or down to play half-diminished seventh chords on other roots.

Inversions of Dm7b5

An inversion puts a note other than the root in the bass. The name is what semicord's chord finder calls those notes played bottom to top; a slash name like C/E means a C chord with E in the bass.

PositionNotes, bass firstNamedListen
Root positionD F Ab CDm7b5
1st inversionF Ab C DFm6 (also read as Dm7b5/F)
2nd inversionAb C D FDm7b5/Ab
3rd inversionC D F AbDm7b5/C

Where Dm7b5 fits

Dm7b5 is viiø7 in Eb major, iiø7 in C minor. As iiø7 it opens the minor ii–V–i: Dm7b5 → G7 → Cm, the minor-key twin of the ii–V–I.