Am7b5 Half-Diminished 7th Chord

The A Half-Diminished 7th chord contains: A, C, D#, G.

These notes are derived by applying the half-diminished 7th interval formula (0–3–6–10 semitones) to the root note A.

Diminished triad with a minor seventh.

Common in jazz as the ii chord in minor keys. The Am7b5 chord is used across pop, rock, jazz, and classical music. As the I chord in the key of A major, it functions as the most stable resting point in progressions.

On piano, play A, C, D#, G simultaneously.

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

A half-diminished 7th chord has 4 notes: A, C, D#, G (in A).

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

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

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

Am7b5 naturally serves as the I chord in the key of A major.

It also appears as IV in the key of E major, and as V in the key of D major.

Yes.

The ukulele uses GCEA tuning with 4 strings. The Am7b5 chord notes (A, C, D#, G) 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 A major, Am7b5 pairs naturally with D major (IV), E major (V), and F#m (vi).

The classic I–IV–V (Am7b5–D–E) is the foundation of blues, country, and rock.

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

Am7b5 root position: A in bass. First inversion: C in bass. Second inversion: D# in bass. Inversions create smoother bass line movement without changing the harmony.

Remember the formula: 0–3–6–10 semitones from root.

For Am7b5: start on A, add 3 semitones, then 6 semitones, then 10 semitones. Practicing this across all 12 roots builds instant recognition of any half-diminished 7th chord.