Root position
G# – B – DThe root G# is the lowest note. This is the shape most people learn first.
3 notes · 1 · ♭3 · ♭5
G# Diminished Piano Chord (G#dim)
G#dim is built from G#, B and D — the formula 1 · ♭3 · ♭5, or 3 and 6 semitones above G#. The shape uses 2 white and 1 black key, and you can hear it, invert it and compare it below.
Chord
G# Diminished
Notes
G# · B · DFormula
1 · ♭3 · ♭5Right hand
1 · 3 · 5C
D
E
F
G
A
B
C
C#
D#
F#
G#
A#
Choose a chord, then play it. Finger numbers run from thumb (1) to little finger (5).
The finder above already holds G#dim. Press P or the Play chord button to hear G#, B, D sounded together, then change the root or the chord type to compare it with something else.
Chord tones
The notes in G#dim
A diminished triad is two minor thirds stacked on top of each other, which squeezes the fifth a semitone flat. The result is tense and unresolved. It appears on the seventh degree of a major scale and on the second degree of a minor key, and it usually leads straight back to a more stable chord.
| Note | Interval | Degree | Semitones | Right hand |
|---|---|---|---|---|
| G#black key | Root | 1 | 0 | 1 · thumb |
| Bwhite key | Minor third | ♭3 | 3 | 3 · middle finger |
| Dwhite key | Diminished fifth | ♭5 | 6 | 5 · little finger |
Step by step
How to play G#dim on piano
- Find G#: it is the middle black key in a group of three.
- Build upwards from G# using 3 and 6 semitones to reach B and D.
- With the right hand, place finger 1 on G#, finger 3 on B and finger 5 on D. Keep the wrist level and the knuckles rounded.
- Move your hand a little further in towards the fallboard so the black key sits comfortably under your fingers.
- Play the notes together, then one at a time from the bottom up, and listen to how G#dim settles.
- Try first inversion as well: B – D – G#. Inversions let you change chords without jumping around the keyboard.
Inversions
G#dim in 3 positions
An inversion keeps the same 3 notes and simply moves the lowest one up an octave. Learning them means you can change chords with small hand movements instead of jumping to a new part of the keyboard.
First inversion
B – D – G#B is the lowest note, so the minor third sits in the bass and the notes below it move up an octave.
Second inversion
D – G# – BD is the lowest note, so the diminished fifth sits in the bass and the notes below it move up an octave.
In context
Which keys contain G#dim
In A major the chord functions as vii°. Altogether it is produced by the scales of 3 keys, so learning it once pays off in several places.
- A majorvii°
- F♯ minorii°
- A harmonic minorvii°
Chord tones are spelled by the degree they occupy, so the third of a minor chord is written as a flat rather than a sharp even though it is the same key on the piano. A double sharp such as F## means the key one whole tone above F.
Compare
G#dim against G# minor
G#dim and G# minor share G# and B. Moving the perfect fifth D# down 1 semitone to the diminished fifth D turns G# minor into G#dim.
Practise the pair together: hold the shared notes G#, B still and move only the one finger. Hearing that single change is the quickest way to recognise the two chords by ear.
Open G# minor →Good questions
G#dim questions
What notes are in the G#dim chord?
G#dim contains G#, B and D. Counted from the root, that is the formula 1 · ♭3 · ♭5, or 3 and 6 semitones above G#.
What is the right-hand fingering for G#dim?
A comfortable beginner fingering is 1 (thumb) on G#, 3 (middle finger) on B and 5 (little finger) on D. Finger numbers run from the thumb (1) to the little finger (5), and they change once you start using inversions.
How is G#dim different from G# minor?
G#dim and G# minor share G# and B. Moving the perfect fifth D# down 1 semitone to the diminished fifth D turns G# minor into G#dim.
Which keys use the G#dim chord?
It occurs naturally in A major (vii°), F♯ minor (ii°) and A harmonic minor (vii°). The roman numeral shows which degree of the key the chord is built on.
What are the inversions of G#dim?
root position is G# – B – D, first inversion is B – D – G# and second inversion is D – G# – B. Every inversion holds the same notes; only the lowest one changes.
Is G#dim the same as the A♭ chord?
On an equal-tempered piano G# and A♭ are the same key, so the chords sound identical. Written music chooses between them according to the key signature: pages here are named after the sharp spelling of the root, and the chord tones are then spelled by the degree each one occupies, which is why a double sharp occasionally appears.