Fdim Chord on Guitar
Fdim = F – G# – B (Root, Minor 3rd, Tritone)
A chord is the same notes however you stack them, and which one sits at the bottom changes how it sounds. The chord builder puts each of Fdim's notes in the bass in turn, names the result, and plays it.
Hear every inversion of Fdim →Fdim breaks from the E-shape barre pattern the rest of this set follows, since diminished triads shrink both the third and fifth, producing a more compact shape at the same demanding first-fret position — with the B string muted outright rather than fretted.
F, G#, and B make up the triad — root, minor third, diminished fifth. As the leading-tone triad (vii°) of Gb(F#) major, Fdim carries strong forward pull toward that tonic, the classic function diminished chords serve: built on the seventh scale degree, they create tension that all but demands resolution up a half step to the chord that follows.
Fingerings
Barre (1st fret)
How to Practice It
Two extra fingers are needed, on the A and D strings, while the B string is deliberately left unfretted and muted rather than played — getting that mute clean takes real care at this particular fret, since the tight first-fret spacing makes it easy for an unintended string to buzz. Because diminished triads are less common in typical guitar rock and folk repertoire, this is also a good chord for training the ear to recognize that particular unstable, searching quality on sight.
Common Progressions
- Fdim – Gb (vii° – I, the classic leading-tone resolution)
- Ebm – Fdim – Gb (vi – vii° – I)
- Cb – Fdim – Gb (IV – vii° – I)
- Gb – Fdim – Gb (a passing diminished color around the tonic)
FAQ
- Why is Fdim's shape different from the other F-rooted barre chords?
- Diminished triads shrink both the third and fifth compared to a major chord, which changes the fret pattern noticeably and also requires muting the B string rather than fretting it.
- Where does Fdim resolve?
- Up a half step to Gb(F#) major, since it functions as the leading-tone diminished triad (vii°) of that key, and diminished chords built on the seventh degree characteristically resolve upward into the tonic that follows.
- Is Fdim hard to play given the first-fret position?
- It's a fairly compact shape in terms of note count, needing only two extra fingers, but muting the B string cleanly at this particular fret takes some practice since the tight spacing makes stray buzzing more likely.
- How common are diminished triads in guitar-based songwriting?
- Less common than major, minor, or seventh chords generally, since their strong, unresolved tension makes them better suited to brief passing moments than sustained harmony.
- Why does a diminished triad sound so unstable?
- Stacking two minor thirds on top of the root produces a diminished fifth instead of a triad's usual stable perfect fifth, and that unstable interval is exactly what gives diminished chords their characteristic searching, tension-filled color.
- Does Fdim ever function outside of Gb major?
- Yes — the same triad also serves as vii° of Gb harmonic minor in certain minor-key contexts, since both keys share F as their leading tone, giving this chord a second plausible resolution.
- Is there a more common way this exact sound appears in practice?
- Guitarists more often reach for the diminished seventh (Fdim7) rather than the plain diminished triad, since the fuller four-note chord is the more standard voicing in jazz and classical-leaning guitar contexts.
Fdim on other instruments: Fdim on Piano, Fdim on Ukulele. Related: how chords are built, chord finder.