A♭ Diminished Chord (Abdim, G#dim) on Piano
The Abdim chord (Ab diminished) is built from 3 notes: Ab – Cb – Ebb. It is also written as G#dim.
Play these notes on a MIDI keyboard, your computer keyboard, or the on-screen keys and ChordKeys will name the chord back to you.
Notes and intervals
| Note | Degree | Interval from Ab | Semitones |
|---|---|---|---|
| Ab | 1 | root | 0 |
| Cb | b3 | minor 3rd | 3 |
| Ebb | b5 | diminished 5th | 6 |
Inversions
Rearranging which note sits at the bottom gives you 3 playable voicings of the same chord. Inversions let you move between chords with less hand movement.
| Voicing | Notes | Bass note |
|---|---|---|
| Root position | Ab – Cb – Ebb | Ab in the bass |
| 1st inversion | Cb – Ebb – Ab | Cb in the bass |
| 2nd inversion | Ebb – Ab – Cb | Ebb in the bass |
How the diminished chord is built
Every diminished chord uses the same interval formula: 1 (0 semitones), b3 (3 semitones), b5 (6 semitones). Starting on Ab and applying that formula produces Ab, Cb, Ebb. Learn the formula once and you can build a diminished chord on any of the twelve roots.
Keys that contain Abdim
Every note of Abdim belongs to these keys, so it will sit naturally in a progression written in any of them.
Other chords on Ab
Diminished chords on other roots
Frequently asked questions
What notes are in a Abdim chord?
A Abdim chord contains the notes Ab, Cb, Ebb. Those are the 1, b3, b5 degrees measured from the root note Ab.
How do you play Abdim on piano?
Place your thumb on Ab, then add Cb and Ebb above it. With a right hand in root position the common fingering is 1–3–5.
Is Abdim the same as G#dim?
Yes. Abdim and G#dim are enharmonic equivalents — they sound identical and use the same piano keys. Which spelling you use depends on the key you are playing in.