A♯ diminished chord (A♯dim)

A♯ diminished is a 3-note diminished chord: A♯ – C♯ – E. It sounds unstable and tense. Here it is on guitar, piano and ukulele, with fingering and audio. Also called B♭ diminished (B♭dim).

NotesA♯ – C♯ – E
Formula1 – ♭3 – ♭5
SymbolA♯dim · A♯° · A♯m♭5
EnharmonicB♭ diminished (B♭dim)

A♯ diminished on guitar

Fret 1 (A shape)
Fret 8 (D shape)

How to place your fingers (fret 1)

Finger 1 (index) on fret 1 of the 5th string (A).
Finger 2 (middle) on fret 2 of the 4th string (D).
Finger 4 (pinky) on fret 3 of the 3rd string (G).
Finger 3 (ring) on fret 2 of the 2nd string (B).
Do not play the 6th and 1st strings: strum from the 5th string.

The numbers inside the dots are the fingers of your left hand: 1 index, 2 middle, 3 ring and 4 pinky. The colored dots mark the root (A♯). The other positions let you change chords without jumping along the neck, or give you a higher-pitched sound.

A♯ diminished on piano

In root position, play A♯ – C♯ – E from bottom to top with fingers 1, 3 and 5 of your right hand (thumb, middle and pinky). With your left hand you usually play just the root (A♯) or the root and the fifth.

Inversions

First inversion: C♯ – E – A♯
Second inversion: E – A♯ – C♯

A♯ diminished on ukulele

Open position
From fret 3

Standard tuning G – C – E – A (the G string is the high one). Is your ukulele in tune? Use the ukulele tuner.

Notes and intervals of A♯ diminished

A♯1 · root
C♯♭3 · minor third
E♭5 · diminished fifth

It's the seventh degree of the major scale and works as a passing chord between two chords a whole step apart.

Progressions with A♯dim

A leading tone that resolves: vii° – I

A♯dim is the seventh degree of B major and leads to B.

Passing chord: I – ♯i° – ii

It climbs by half steps between two chords a whole step apart.

Which keys contain A♯ diminished?

A♯dim belongs to 2 keys: in each one it plays a different role depending on the degree (the Roman numeral).

Key	Degree
B major	vii°
G♯ natural minor	ii°

Frequently asked questions

What notes are in the A sharp diminished chord?

A♯ diminished (A♯dim) has 3 notes: A♯ (root), C♯ (minor third), E (diminished fifth).

How do you play A♯ diminished on guitar?

The most common shape starts at fret 1: x 1 2 3 2 x (from the 6th to the 1st string). Finger 1 (index) at fret 1 on the 5th string (A). Finger 2 (middle) at fret 2 on the 4th string (D). Finger 4 (pinky) at fret 3 on the 3rd string (G). Finger 3 (ring) at fret 2 on the 2nd string (B). Don't play the 6th or 1st strings: strum from the 5th.

Is A♯dim the same as B♭dim?

Yes: A♯ diminished and B♭ diminished sound the same and are played the same way (they're enharmonic). The spelling depends on the song's key; you'll see both names in sheet music and songbooks.

How do you write A♯ diminished in letter chord notation?

It is written A♯dim; you may also see A♯° or A♯m♭5. Letter notation uses C, D, E, F, G, A and B for the seven note names.

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