Explore the A#dim7 Guitar Chord: Sound, Shapes & Interactive Practice
Looking for A diminished seventh, one fret lower? Visit Adim7.
A# diminished seventh (written A#dim7) takes its name from its interval stack, the root, minor third, flat five and diminished seventh, which gives the notes A#, C#, E and G. The seventh is a diminished seventh, which is spelled as a seventh although it sounds like a major sixth above the root. Open strings feature in one of the 8 voicings on this page.
Every note of A#dim7 sits inside the A# whole-half scale, so that scale is the natural place to look for melody notes. Press play in the chord player at the top of the page to hear A#dim7 strummed, then picked as an arpeggio. Seen from the other side, Bbdim7 names the same sound with the opposite accidentals.
A# diminished 7th guitar chord is also written as A#dim7, A#°7 or A#o7. It is also known as the A# fully diminished seventh chord.
A#dim7 Chord Notes and Formula
Notes that compose the A# dim7 chord:
Tones in the Diminished Seventh chord:
Formula: 1 b3 b5 bb7
Same chord, different name: A#dim7 is also written as Bbdim7 (Bb diminished seventh).
A#dim7 Chord Interactive Fretboard
Want a structured chord roadmap instead of jumping between pages?
Go to the full guitar chords tutorial.
A#dim7 Guitar Chord Diagrams
Position 1 Movable
A# Diminished Seventh Finger Positions
- Mute the B string
- Mute the high E string
- Place your index finger (1) on the fret 2 of the D string
- Place your middle finger (2) on the fret 3 of the low E string
- Place your ring finger (3) on the fret 3 of the G string
- Place your pinky finger (4) on the fret 4 of the A string
Position 2 Movable
A# Diminished Seventh Finger Positions
- Mute the low E string
- Mute the high E string
- Place your index finger (1) on the fret 3 of the G string
- Place your middle finger (2) on the fret 4 of the A string
- Place your ring finger (3) on the fret 5 of the D string
- Place your pinky finger (4) on the fret 5 of the B string
Position 3 Movable
A# Diminished Seventh Finger Positions
- Mute the low E string
- Mute the A string
- Place your index finger (1) on the fret 8 of the D string
- Place your middle finger (2) on the fret 8 of the B string
- Place your ring finger (3) on the fret 9 of the G string
- Place your pinky finger (4) on the fret 9 of the high E string
Position 4 Open
A# Diminished Seventh Finger Positions
- Mute the low E string
- Let the G string play without pressing any fret
- Mute the high E string
- Place your index finger (1) on the fret 1 of the A string
- Place your middle finger (2) on the fret 2 of the D string
- Place your ring finger (3) on the fret 2 of the B string
Position 5 Movable
A# Diminished Seventh Finger Positions
- Mute the A string
- Mute the B string
- Mute the high E string
- Place your index finger (1) on the fret 5 of the D string
- Place your middle finger (2) on the fret 6 of the low E string
- Place your ring finger (3) on the fret 6 of the G string
Position 6 Movable
A# Diminished Seventh Finger Positions
- Mute the A string
- Mute the B string
- Mute the high E string
- Place your index finger (1) on the fret 8 of the D string
- Place your middle finger (2) on the fret 9 of the low E string
- Place your ring finger (3) on the fret 9 of the G string
Position 7 Movable
A# Diminished Seventh Finger Positions
- Mute the A string
- Mute the high E string
- Place your index finger (1) on the fret 5 of the D string
- Place your middle finger (2) on the fret 5 of the B string
- Place your ring finger (3) on the fret 6 of the low E string
- Place your pinky finger (4) on the fret 6 of the G string
Position 8 Movable
A# Diminished Seventh Finger Positions
- Mute the low E string
- Mute the high E string
- Place your index finger (1) on the fret 6 of the G string
- Place your middle finger (2) on the fret 7 of the A string
- Place your ring finger (3) on the fret 8 of the D string
- Place your pinky finger (4) on the fret 8 of the B string
Find more shapes in our all guitar chords online library. If you
prefer a printable pdf, download
the Free Guitar Chords Chart Pdf
Chords That Go With A#dim7
One key where A#dim7 fits is B minor, where it works as the vii°7 chord, built on the raised 7th of the harmonic minor, so it pulls straight to the tonic. These are the main chords of that key, the ones you will often hear around it:
See every key in the guitar keys chart, or build a progression with these chords in the chord progression generator.
More A# Chords
Want to know how this chord is built? Read diminished and half-diminished chords, or browse all A# guitar chords.
Created by
Giancarlo is a musician (teaching guitar since 2000), software engineer, AI consultant and published researcher
FAQ
What are the notes of A#dim7?
A#dim7 is spelled A#, C#, E and G. That is the root, a minor third, a flat fifth and a diminished seventh. Each neighbouring pair is a minor third, three semitones apart.
Is A#dim7 the same chord as Bbdim7?
Yes. A#dim7 and Bbdim7 are two names for the same pitches, so they sound identical. A#dim7 uses simple sharp spelling, while Bbdim7 needs the double flat Abb.
Which scale covers all of A# diminished seventh?
The A# whole-half scale. It alternates whole and half steps, and every note of A#, C#, E and G appears in it, so it is a good source for melody notes.
Why does a diminished seventh sound like a major sixth?
A diminished seventh lies nine semitones from the root, and a major sixth lies there too. In A#dim7, the G is spelled as a seventh but sounds like a sixth over A#.
In which harmonic minor key is A#dim7 the vii chord?
A#dim7 is the vii chord of B harmonic minor, built on the raised seventh degree. Its four notes all appear in that scale, and the chord leads toward B minor.
How many A#dim7 voicings can be played?
There are 8 voicings, and 1 of them uses an open string. None needs a barre. They run from fret 1 up to fret 9.
