Chord Information
Learn how to play A#m7b5 on piano
Notes in Chord
Intervals
Inversion
Notes (bottom to top): A#4 - C#5 - E5 - G#5
Right Hand Fingering
3=middle, 4=ring, 5=pinky
Interactive Piano
Click the highlighted keys to play the A#m7b5 chord
About the A#m7b5 Chord
The A#m7b5 chord exists primarily in theory, with its enharmonic equivalent Bbm7b5 appearing in most practical music. Built from A#-C#-E-G#, this chord would function in extremely sharp contexts, but Bbm7b5 (Bb-Db-Fb-Ab) is the common spelling.
Understanding A#m7b5's relationship to Bbm7b5 helps with transposition and theory. For pianists, they're physically identical—the same keys produce the same dark half-diminished sound.
The chord functions as ii in G# minor (extremely rare) or more commonly as Bbm7b5 functioning as ii in Ab minor.
Music Theory & Usage
A#m7b5/Bbm7b5 functions as ii in G#/Ab minor respectively. Bbm7b5 appears in jazz standards requiring Ab minor harmony.
In practical music, Bbm7b5 is the standard spelling—Ab minor is far more common than G# minor.
Famous Songs Using A#m7b5
Hear how professional musicians use the A#m7b5 chord in these well-known songs:
“Note: Usually written as Bbm7b5”
by Various
This chord is typically notated as Bbm7b5
“On Green Dolphin Street”
by Bronislau Kaper
Uses half-diminished chords
“Days of Wine and Roses”
by Henry Mancini
Features m7b5 voicings
“Emily”
by Johnny Mandel
Contains half-diminished in its changes
How to Play A#m7b5 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#m7b5 chord.
Recommended fingering: 1-2-3-5 (right hand)
A#m7b5 Chord Inversions
The A#m7b5 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#m7b5
ii-V-I Jazz Progression
Common chord progression
I-vi-ii-V Progression
Common chord progression
Practice Tips for A#m7b5
- Start slowly and focus on pressing all keys simultaneously for a clean sound.
- Practice transitioning between A#m7b5 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#m7b5
Is A#m7b5 the same as Bbm7b5?
Yes, enharmonically identical. Bbm7b5 (Bb-Db-Fb-Ab) is standard in practical music. A#m7b5 (A#-C#-E-G#) exists mainly in theory.
What notes are in A#m7b5?
A#m7b5 contains A# (root), C# (minor 3rd), E (diminished 5th), and G# (minor 7th). Same pitches as Bb-Db-Fb-Ab.
What key is Bbm7b5 the ii chord of?
Bbm7b5 is the ii chord in Ab minor. The progression Bbm7b5-Eb7-Abm is the minor ii-V-i in Ab.
Which spelling should I use?
Use Bbm7b5 in virtually all practical contexts. A#m7b5 might appear only in extreme sharp-key analysis.