Root position
F# – A – CThe root F# is the lowest note. This is the shape most people learn first.
3 notes · 1 · ♭3 · ♭5
F# Diminished Piano Chord (F#dim)
F#dim is built from F#, A and C — the formula 1 · ♭3 · ♭5, or 3 and 6 semitones above F#. The shape uses 2 white and 1 black key, and you can hear it, invert it and compare it below.
Chord
F# Diminished
Notes
F# · A · CFormula
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 F#dim. Press P or the Play chord button to hear F#, A, C sounded together, then change the root or the chord type to compare it with something else.
Chord tones
The notes in F#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 |
|---|---|---|---|---|
| F#black key | Root | 1 | 0 | 1 · thumb |
| Awhite key | Minor third | ♭3 | 3 | 3 · middle finger |
| Cwhite key | Diminished fifth | ♭5 | 6 | 5 · little finger |
Step by step
How to play F#dim on piano
- Find F#: it is the first black key in a group of three.
- Build upwards from F# using 3 and 6 semitones to reach A and C.
- With the right hand, place finger 1 on F#, finger 3 on A and finger 5 on C. 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 F#dim settles.
- Try first inversion as well: A – C – F#. Inversions let you change chords without jumping around the keyboard.
Inversions
F#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
A – C – F#A is the lowest note, so the minor third sits in the bass and the notes below it move up an octave.
Second inversion
C – F# – AC 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 F#dim
In G 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.
- G majorvii°
- E minorii°
- G 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
F#dim against F# minor
F#dim and F# minor share F# and A. Moving the perfect fifth C# down 1 semitone to the diminished fifth C turns F# minor into F#dim.
Practise the pair together: hold the shared notes F#, A still and move only the one finger. Hearing that single change is the quickest way to recognise the two chords by ear.
Open F# minor →Good questions
F#dim questions
What notes are in the F#dim chord?
F#dim contains F#, A and C. Counted from the root, that is the formula 1 · ♭3 · ♭5, or 3 and 6 semitones above F#.
What is the right-hand fingering for F#dim?
A comfortable beginner fingering is 1 (thumb) on F#, 3 (middle finger) on A and 5 (little finger) on C. Finger numbers run from the thumb (1) to the little finger (5), and they change once you start using inversions.
How is F#dim different from F# minor?
F#dim and F# minor share F# and A. Moving the perfect fifth C# down 1 semitone to the diminished fifth C turns F# minor into F#dim.
Which keys use the F#dim chord?
It occurs naturally in G major (vii°), E minor (ii°) and G harmonic minor (vii°). The roman numeral shows which degree of the key the chord is built on.
What are the inversions of F#dim?
root position is F# – A – C, first inversion is A – C – F# and second inversion is C – F# – A. Every inversion holds the same notes; only the lowest one changes.
Is F#dim the same as the G♭ chord?
On an equal-tempered piano F# and G♭ 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.