Fdim

Q: What notes are in the Fdim chord?

The Fdim chord (F Diminished) contains: F, Ab, Cb. Its interval structure is shown above in the Theory section.

Q: How do I build Fdim on the keyboard?

Take the root and add the remaining chord tones following the interval formula. The highlight shows chord content, while the inversion control changes which chord tone is in the bass.

Q: Which keys is Fdim found in?

The chord acts as a diatonic degree in several keys — they are marked on the circle of fifths in the "Harmonic context" block.

Q: What can I substitute for Fdim?

A substitution depends on harmonic function and voice leading, not only on shared tones. Computed options appear in the "Substitutions" block and should be checked in context.

F Diminished

Octaves

Musical context

ChordFdimF Diminished

ArpeggioF minorBroken triad

ScaleF minor7 notes

KeyF minorMinor key

ProgressionAndalusianSequence

How the chord relates to the scale, mode, key and progression.

Theory

General info

Full name: F Diminished
Symbol: Fdim
Root: F
Quality: Diminished

Chord notes

1Froot

b3Abminor 3rd

b5Cbdim 5th

Functions & resolutions

Typical function in key: iiiMediant (iii)C# major
Stability / tension: Maximum tension — extremely unstable
Most common resolutions: GbGb Major AA Major
Unstable degrees: 2G
b3Ab
resolves down to the 2nd
4Bb
b5B
resolves inward to the 4th
Main resolution: Fdimsource
GbGb Major
Diminished Fdim acts as a leading-tone chord — resolves up a half step to Gb. All tones are unstable, moving by semitones inward and outward to stable degrees.
Other resolutions: Fdimsource
Deceptive resolution
AA Major
Due to its symmetry, a diminished 7th chord can resolve to any major or minor chord a minor 3rd apart.
Fdimsource
Modal resolution
GmG Minor
In modal context, a diminished chord can be used as a passing chord, connecting two diatonic chords through chromatic bass motion.
Fdimsource
Jazz reharmonization
E7E Dominant 7
In jazz, dim7 is often reinterpreted as a rootless dominant 7b9. For example, Fdim7 ≈ E7b9, opening additional resolution paths.
Fdimsource
Functional resolution
CmC Minor
A diminished chord can function as a leading-tone chord to any degree — not just the tonic. Often used before the ii, iii, or vi degrees.

Features

Character: Diminished, unstable
Characteristic interval: Diminished 5th (b5)
Description: Two stacked minor 3rds form a diminished 5th. The tritone makes the triad dissonant and directs voices toward neighbouring stable tones.
Application: vii° — vii degree of major
Passing chords
Horror, suspense