Sevenths
F diminished 7th chord
Symmetrical and very tense — every note is a minor 3rd apart.
Fdim7 is the vii°7 chord in F♯ minor.
- Notes
- FA♭C♭E𝄫
- Formula
- 1♭3♭5𝄫7
- Built from
- root · minor 3rd · diminished 5th · diminished 7th
How to play Fdim7
About the F diminished 7th chord
Playing it
On guitar, Fdim7 has an open-position shape, 120404, using four fingers alongside the open strings.
On piano, Fdim7 has one black key (A♭) and three white keys.
On ukulele the usual Fdim7 shape is 1212, using four fingers.
Related chords
Take away the root and the other three notes form A♭dim (A♭ C♭ E𝄫) — so you can think of Fdim7 as A♭dim with F added underneath.
Fdim7 is symmetrical — its notes are evenly spaced — so Ddim7, A♭dim7 and Bdim7 contain exactly the same notes. There are only three different-sounding diminished 7th chords in all.
Move a single note and Fdim7 becomes a different chord: drop the E𝄫 for Fdim, raise C♭ to C for Fm6 and raise E𝄫 to E♭ for Fm7♭5.
Where you’ll hear it
Notice the C♭ in Fdim7 (F A♭ C♭ E𝄫): each note of the chord takes its own letter (F–A–C–E), so the diminished 5th has to be written C♭ rather than B — the same key on a piano, spelled to fit the chord.
