A♭ Diminished 7th
Also Known As
Hear the A♭ Diminished 7th chord played for you.
A♭°7
A♭ – B – D – F
Formula:R-m3-d5-d7
Intervals:P1-m3-d5-d7
Scale Degrees:1-b3-b5-bb7
Introduction
The A♭ Diminished 7th chord is a four-note chord made up of A♭, B, D, and F. It is built from a root, minor third, diminished fifth, and diminished seventh.
The Ab Diminished 7th piano chord (Abdim7) consists of the notes Ab, B, D, F. It is built by stacking three minor thirds, creating a fully symmetrical 4-note chord, giving it a extremely tense and dramatic character, fully symmetrical and harmonically versatile. Formula: R-m3-d5-d7 | Scale degrees: 1-b3-b5-bb7.
Notes
A♭ Diminished 7th Inversions
| Position | Notes |
|---|---|
| Root Position | Ab – B – D – F |
| 1st Inversion | B – D – F – Ab |
| 2nd Inversion | D – F – Ab – B |
| 3rd Inversion | Ab – B – D – F |
Key Signature
The key of Ab Diminished 7th has 4 flats.
B♭E♭A♭D♭
Order of flats
Flats are added in a fixed order — the reverse of the sharp order. Each new flat key adds the next flat on the list.
B♭E♭A♭D♭G♭C♭F♭
Mnemonic: Battle Ends And Down Goes Charles’ Father
Chords in the Key of Ab Major
These are the diatonic triads built on each degree of the Ab major scale:
C
D
E
F
G
A
B
C
D
E
F
G
A
B
I — A♭ Major (major)
Theory: Intervals
Formula: R-m3-d5-d7
Intervals: P1-m3-d5-d7
The A♭ Diminished 7th is built by stacking intervals from the root note. The formula R-m3-d5-d7 describes the scale degrees used. The intervals P1-m3-d5-d7 show the distance between each note in the chord.
A♭ Diminished 7th — Frequently Asked Questions
What notes are in the Ab Diminished 7th chord?
The Ab Diminished 7th chord (Abdim7) contains four notes: Ab (root), Cb (minor third, enharmonically B), Ebb (diminished fifth, enharmonically D), and Gbb (diminished seventh, enharmonically F). All four notes are spaced exactly 3 semitones apart.
How does Ab Diminished 7th differ from Ab Diminished?
Ab Diminished is a three-note triad (Ab, Cb, Ebb). Ab Diminished 7th adds Gbb/F as the diminished seventh, completing the symmetrical structure.
Why is the Diminished 7th chord symmetrical?
Abdim7 contains the same pitches as Ddim7, Fdim7, and Bdim7 — all inversions of the same four notes (D, F, Ab, B). Only three unique dim7 chords exist.
How is Ab Diminished 7th used in music?
Abdim7 functions as the vii°7 of A, resolving up by half step to A Major or A minor. It works as a dramatic chromatic passing chord and is common in classical cadences and jazz turnarounds.
What songs use Diminished 7th chords?
Diminished 7th chords appear in Michelle (Beatles), throughout Chopin and Beethoven, and in jazz standards. Film scores and musical theatre use dim7 for dramatic tension.
How many unique Diminished 7th chords exist?
Only three. Abdim7 shares its notes with Ddim7, Fdim7, and Bdim7. The other two groups are Cdim7 and Dbdim7.
Practice Tips
- Play Abdim7 and Ddim7 — same notes rearranged, proving the three-chord symmetry.
- Abdim7 resolves to A Major: try Abdim7 → A for the leading-tone resolution.
- Use as a chromatic passing chord: Ab Major → Abdim7 → Am7 for smooth jazz movement.
- The enharmonic pitches (Ab–B–D–F) reveal the physical keyboard pattern — alternating black and white keys.
- Practice all four inversions: each sounds equally tense, unlike major or minor chords where inversions have different characters.
- Compare Abdim7 with Abm7 — both start on Ab, but dim7 has maximum tension while m7 is smooth and dark.
Related Tools
Chord FinderLook up any chord — see the notes, hear it, and play along.Chord DrillTimed drills to build speed and recognition across all chord types.Practice RoomPlug in a MIDI keyboard and get real-time feedback on every chord and scale.Circle of FifthsVisualize key relationships, relative minors, and key signatures.MIDI MonitorLive MIDI message stream with note names, velocity, and a scrolling staff.