F♯dim
F# Diminished — tense and unstable by design — built from stacked minor thirds, it begs to resolve.
The keys
F♯ – A – C
What's inside F♯dim
| Note | Interval from root | Degree |
|---|---|---|
| F♯ | Root | 1 |
| A | Minor 3rd | b3 |
| C | Diminished 5th | b5 |
Inversions
| Position | Keys (low → high) |
|---|---|
| Root position | G♭4 – A4 – C5 |
| 1st inversion | A4 – C5 – G♭5 |
| 2nd inversion | C5 – G♭5 – A5 |
A working voicing
Split the chord between two hands the way working players do — a solid shell low down, the colour tones up top:
| Hand | Keys |
|---|---|
| Left (shell) | G♭2 – G♭3 |
| Right (colour) | A4 – C5 |
Where F♯dim lives
As the I chord
F♯dim → B → D♭ → F♯dim
The classic I–IV–V–I motion with this chord as home.
In a ii–V–I
A♭m7 → D♭7 → F♯dim
The strongest cadence in harmony, resolving onto this chord.
Put F♯dim under your fingers
Hear every voicing, see the keys light up, and drill it in the interactive Chord & Voicing Lab.
Open the Chord & Voicing Lab →