Chord Information
Learn how to play A#dim7 on piano
Notes in Chord
Intervals
Inversion
Notes (bottom to top): A#4 - C#5 - E5 - G5
Right Hand Fingering
3=middle, 4=ring, 5=pinky
Interactive Piano
Click the highlighted keys to play the A#dim7 chord
About the A#dim7 Chord
The A#dim7 chord exists primarily in theory, with its enharmonic equivalent Bbdim7 appearing in most practical music. Built from A#-C#-E-G, this fully diminished seventh chord shares pitches with C#dim7, Edim7, and Gdim7.
Understanding A#dim7's relationship to Bbdim7 helps with transposition and analysis, but Bbdim7 is what you'll encounter in real music. The flat spelling is cleaner and more common.
The chord's pitch collection is extremely common—it appears constantly as a passing chord and viidim7 function.
Music Theory & Usage
A#dim7/Bbdim7 commonly functions as viidim7 in B/Cb major, as a passing chord, or as chromatic color. Its symmetry with C#/Dbdim7, Edim7, and Gdim7 provides flexibility.
Bbdim7 (the practical spelling) appears throughout jazz standards and classical music wherever chromatic passing motion is needed.
Famous Songs Using A#dim7
Hear how professional musicians use the A#dim7 chord in these well-known songs:
“Note: Usually written as Bbdim7”
by Various
This chord is typically notated as Bbdim7
“All the Things You Are”
by Jerome Kern
Uses dim7 passing chords
“Have You Met Miss Jones”
by Richard Rodgers
Features Bbdim7 for chromatic movement
“Cherokee”
by Ray Noble
Contains dim7 for harmonic sophistication
How to Play A#dim7 on Piano
- Place your thumb on A#.
- Place your index finger on C#.
- Place your middle finger on E.
- Place your pinky finger on G.
- Press all keys simultaneously to hear the A#dim7 chord.
Recommended fingering: 1-2-3-5 (right hand)
A#dim7 Chord Inversions
The A#dim7 chord can be played in different inversions:
Root Position
A# - C# - E - G (bass note: A#)
First Inversion
C# - E - G - A# (bass note: C#)
Second Inversion
E - G - A# - C# (bass note: E)
Common Chord Progressions Using A#dim7
ii-V-I Jazz Progression
Common chord progression
I-vi-ii-V Progression
Common chord progression
Practice Tips for A#dim7
- Start slowly and focus on pressing all keys simultaneously for a clean sound.
- Practice transitioning between A#dim7 and other common chords to build muscle memory.
- Listen carefully to how the seventh interval creates tension and color in the chord.
- Practice resolving this chord to its natural target chords in progressions.
Frequently Asked Questions about A#dim7
Is A#dim7 the same as Bbdim7?
Yes, enharmonically identical. Bbdim7 (Bb-Db-Fb-Abb) is the common spelling. Both contain Bb, Db, E/Fb, and G.
What notes are in A#dim7?
A#dim7 contains A# (root), C# (minor 3rd), E (diminished 5th), and G (diminished 7th). Same pitches as Bbdim7.
What chords share these pitches?
A#/Bbdim7, C#/Dbdim7, Edim7, and Gdim7 all contain the same pitch collection—inversions of each other.
When would I see A#dim7 written?
Rarely in practical music. Bbdim7 is standard. A#dim7 might appear in theoretical exercises or when analyzing sharp-key passages.