F diminished chord

The vii° of F♯ major: three notes that lean straight into F♯.

How it sounds
Tense and unstable. Both gaps are three frets, F to A♭ and A♭ to C♭, so the fifth sits a fret flat and nothing in the chord settles. There’s no open grip. The lowest of its four grips is the E-root form, at the 1st fret.
Where it lives
The vii° of F♯ major, the ii° of E♭ minor and the vii° of F♯ harmonic minor. Rarely a chord you stay on: it passes between chords, or stands in for C♯7 on the way to F♯, since it’s C♯7 without the C♯. In F♯ major and F♯ harmonic minor the same chord is written E♯dim. Jazz, gospel and classical harmony, where passing chords are everyday. Rock and pop use it much less.

Voicings across the neck

F, A♭ and C♭ are shown in four places on the neck. Every grip uses four strings, so one of the three notes is doubled, and each takes its name from the string its root sits on. Mute the other two. The lowest is the E-root form at the 1st fret, and the highest the A-root form at the 8th.

Show
I.
E-root form · 1st fret
  • High E string: not played
  • B string: not played
  • G string: A♭ at fret 1
  • D string: F at fret 3
  • A string: C♭ at fret 2
  • Low E string: F at fret 1
II.
D-root form · 3rd fret
  • High E string: A♭ at fret 4
  • B string: F at fret 6
  • G string: C♭ at fret 4
  • D string: F at fret 3
  • A string: not played
  • Low E string: not played
III.
G-root form · 7th fret
  • High E string: C♭ at fret 7
  • B string: A♭ at fret 9
  • G string: F at fret 10
  • D string: C♭ at fret 9
  • A string: not played
  • Low E string: not played
IV.
A-root form · 8th fret
  • High E string: not played
  • B string: A♭ at fret 9
  • G string: F at fret 10
  • D string: C♭ at fret 9
  • A string: F at fret 8
  • Low E string: not played

Formula

IntervalsNotesSemitones
R · m3 · d5: what each interval does in a chordF · A♭ · C♭3 + 3

F diminished is a root, a minor third and a diminished fifth: F, A♭ and C♭. Three then three is what makes it diminished, two minor thirds stacked, so the fifth lands a fret below a perfect one. Raise C♭ a fret to C and you get F minor.

How chords are built from a scale

What each interval does

In these keys and scales

F diminished turns up in six scales on the site, and it’s home in none of them. In F♯ major it’s the vii° (written E♯dim there), a fret below F♯. In E♭ minor and E♭ harmonic minor it’s the ii°. F♯ harmonic minor and F♯ melodic minor both raise their seventh note to E♯, so it’s their vii° too (E♯dim there too), and in G♯ melodic minor it’s the vi° (E♯dim there too). The numeral beside each scale names the job, and the name opens that scale’s page.

The scales on the site with Fdim in them, by family
FamilyScales
Major
Natural minor
Harmonic minor
Melodic minor

Progressions

Fdim hardly ever ends a phrase, and in all three of these it’s on its way somewhere. In vii°–⁠I it resolves up a fret, F to G♭. In I–⁠vii°–⁠vi it’s the middle step of a bass line walking down, G♭, F, E♭. In ii°–⁠V–⁠i it opens the minor cadence, and B♭ carries it the rest of the way to E♭m.

Progressions with Fdim in them
NameNumeralsChords
The leading tone, resolvedvii°–IFdim – G♭
The passing stepI–vii°–viG♭ – Fdim – E♭m
The minor cadenceii°–V–iFdim – B♭ – E♭m