Ddim7 Diminished 7th Chord

The D Diminished 7th chord contains: D, F, G#, B.

These notes are derived by applying the diminished 7th interval formula (0–3–6–9 semitones) to the root note D.

Four notes stacked in minor thirds.

Extremely tense, used as a passing chord. The Ddim7 chord is used across pop, rock, jazz, and classical music. As the I chord in the key of D major, it functions as the most stable resting point in progressions.

On piano, play D, F, G#, B simultaneously.

In root position, D is the lowest note. Inversions move the bass note up — first inversion has F lowest, second inversion has G# lowest.

A diminished 7th chord has 4 notes: D, F, G#, B (in D).

It is a 7th chord, extending beyond the basic triad.

The D major chord (D–F#–A) uses a major third (4 semitones), giving it a bright, happy sound.

The D minor chord (D–F–A) uses a minor third (3 semitones), giving it a darker, emotional sound.

Ddim7 naturally serves as the I chord in the key of D major.

It also appears as IV in the key of A major, and as V in the key of G major.

Yes.

The ukulele uses GCEA tuning with 4 strings. The Ddim7 chord notes (D, F, G#, B) can be fretted on a ukulele, though the shapes differ from guitar due to the 4-string layout and shorter scale.

In the key of D major, Ddim7 pairs naturally with G major (IV), A major (V), and Bm (vi).

The classic I–IV–V (Ddim7–G–A) is the foundation of blues, country, and rock.

An inversion places a non-root note in the bass.

Ddim7 root position: D in bass. First inversion: F in bass. Second inversion: G# in bass. Inversions create smoother bass line movement without changing the harmony.

Remember the formula: 0–3–6–9 semitones from root.

For Ddim7: start on D, add 3 semitones, then 6 semitones, then 9 semitones. Practicing this across all 12 roots builds instant recognition of any diminished 7th chord.