A Diminished Chord (Adim) on Piano
The Adim chord (A diminished) is built from 3 notes: A – C – Eb.
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 A | Semitones |
|---|---|---|---|
| A | 1 | root | 0 |
| C | b3 | minor 3rd | 3 |
| Eb | 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 | A – C – Eb | A in the bass |
| 1st inversion | C – Eb – A | C in the bass |
| 2nd inversion | Eb – A – C | Eb 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 A and applying that formula produces A, C, Eb. Learn the formula once and you can build a diminished chord on any of the twelve roots.
Keys that contain Adim
Every note of Adim belongs to these keys, so it will sit naturally in a progression written in any of them.
Other chords on A
Diminished chords on other roots
Frequently asked questions
What notes are in a Adim chord?
A Adim chord contains the notes A, C, Eb. Those are the 1, b3, b5 degrees measured from the root note A.
How do you play Adim on piano?
Place your thumb on A, then add C and Eb above it. With a right hand in root position the common fingering is 1–3–5.