F Diminished

Notes:F – Ab – B
Formula:R-m3-d5
Intervals:P1-m3-d5
Scale Degrees:1-b3-b5

Introduction

The F Diminished piano chord (Fdim) consists of the notes F, Ab, B. It is built by stacking two minor thirds (3 semitones each), giving it a tense, unstable, and dissonant character. Formula: R-m3-d5 | Scale degrees: 1-b3-b5.

Notes

Notes:F – Ab – B

F Diminished Inversions

PositionNotes
Root PositionF4 – Ab4 – B4
1st InversionAb4 – B4 – F5
2nd InversionB4 – F5 – Ab5

Key Signature

The key of F Diminished has 1 flat: B♭.

B

Theory: Intervals

Formula: R-m3-d5
Intervals: P1-m3-d5

The F Diminished is built by stacking intervals from the root note. The formula R-m3-d5 describes the scale degrees used. The intervals P1-m3-d5 show the distance between each note in the chord.

F Diminished — Frequently Asked Questions

What notes are in the F Diminished chord?

The F Diminished chord contains: F (root), Ab (minor third), and Cb (diminished fifth). Both intervals are compressed: the minor third is 3 semitones above the root, and the diminished fifth is 6 semitones — a tritone.

How does F Diminished differ from F Minor?

F Minor has a perfect fifth. F Diminished lowers the fifth by one semitone to Cb (diminished fifth). That extra compression creates intense harmonic tension — the tritone between root and diminished fifth is the most dissonant interval in Western music.

What is the symbol for the F Diminished?

F Diminished is written as Fdim or F°. The ° or "dim" symbol means both the third and fifth are minor/diminished. Do not confuse with Fdim7 or Fø (half-diminished), which include additional notes.

What are the inversions of F Diminished?

First inversion (F Diminished/Ab): Ab–Cb–F. Second inversion (F Diminished/Cb): Cb–F–Ab. Diminished triads are used in classical music as the vii° chord — the chord one semitone below the tonic, with strong resolution pull.

How is F Diminished used in music?

F Diminished most commonly functions as the vii° chord in a major key, creating strong resolution back to the tonic. It also works as a chromatic passing chord between two nearby chords, and in classical music as a brief point of dissonance. Jazz uses the full four-note dim7 more often than the triad.

What songs use diminished chords?

Michelle (Beatles) uses a diminished chord as a chromatic passing chord. Many classical pieces use vii°–I cadences. Jazz standards use dim7 chords as chromatic passing and approach chords. Diminished harmony also appears in flamenco and film music for dramatic tension.

Practice Tips

  • Compare F Minor and F Diminished: only the fifth changes (Cb vs perfect fifth). Play both back to back — the extra compression is striking.
  • The tritone between F and Cb creates maximum tension — practice just this two-note interval to hear its characteristic sound.
  • F Diminished most naturally resolves up by half step: play Fdim then a chord whose root is F raised by one semitone.
  • Practice all inversions: F–Ab–Cb, Ab–Cb–F, Cb–F–Ab.
  • Use F Diminished as a vii° chord: it is one semitone below F# Major — try Fdim → F# Major to feel this powerful classical resolution.
  • In a major key, find where F Diminished fits naturally as a passing chord between two diatonic chords a step apart.