F diminished chord on bass (Fdim)

Also called or written Fdim or

F diminished contains F, A♭, and C♭. The 1st-fret shape is a one-finger-per-string stretch that sits low on the neck.

FC♭FA♭EADG
Positions on the neck1 of 5
Practice F diminished chord

How it is built

FRootA♭Minor thirdC♭Diminished fifth

Formula 1, ♭3, ♭5

Inversions

How do you play an F diminished chord on bass?

F diminished is played at the 1st fret as 1 2 3 1: index finger on the E string at fret 1, ring finger on the A string at fret 2, pinky finger on the D string at fret 3 and middle finger on the G string at fret 1.

Full note and interval breakdown
StringFretFingerNote
4 (E)11F (1)
3 (A)23C♭ (♭5)
2 (D)34F (1)
1 (G)12A♭ (♭3)

IntermediateThe pinky must reach the 3rd fret on the 2nd string while the middle finger holds the 1st fret on the 1st string.

13th fret

F diminished is played at the 13th fret as 13 14 15 13: index finger on the E string at fret 13, ring finger on the A string at fret 14, pinky finger on the D string at fret 15 and middle finger on the G string at fret 13.

Full note and interval breakdown
StringFretFingerNote
4 (E)131F (1)
3 (A)143C♭ (♭5)
2 (D)154F (1)
1 (G)132A♭ (♭3)

Fdim/A♭ inversion

F diminished is played at the 2nd fret as 4 2 3 4: ring finger on the E string at fret 4, index finger on the A string at fret 2, middle finger on the D string at fret 3 and pinky finger on the G string at fret 4.

Full note and interval breakdown
StringFretFingerNote
4 (E)43A♭ (♭3)
3 (A)21C♭ (♭5)
2 (D)32F (1)
1 (G)44C♭ (♭5)

Fdim/C♭ inversion · fret 1

F diminished is played at the 1st fret as × 2 3 1: middle finger on the A string at fret 2, ring finger on the D string at fret 3 and index finger on the G string at fret 1. The E string stays muted.

Full note and interval breakdown
StringFretFingerNote
4 (E)muted
3 (A)22C♭ (♭5)
2 (D)33F (1)
1 (G)11A♭ (♭3)

Fdim/C♭ inversion · fret 6

F diminished is played at the 6th fret as 7 8 6 ×: middle finger on the E string at fret 7, ring finger on the A string at fret 8 and index finger on the D string at fret 6. The G string stays muted.

Full note and interval breakdown
StringFretFingerNote
4 (E)72C♭ (♭5)
3 (A)83F (1)
2 (D)61A♭ (♭3)
1 (G)muted

Why it sounds like that

F diminished is built from the formula 1, ♭3, ♭5. The ♭5 interval gives the chord its tense, unstable quality. Compare F minor, which raises the fifth to C.

What goes wrong with F diminished?

  • Letting the pinky collapse onto the 1st string mutes the G.
  • Pressing the index finger too flat on the 4th string buzzes against the fret.
  • Arching the ring finger too high pulls the 3rd string sharp.

When to use it

F diminished works as a passing chord between F minor and A♭ major, or over an E♭ natural minor line. The ♭5 interval creates a tritone that pulls toward the next chord, suiting jazz walk-ups and metal riffs.

Changing to and from F diminished

  • Sliding the shape up one fret to the 2nd fret gives F♯ diminished.
  • Move to F minor by raising the 2nd string one fret to the 4th fret.

Which voicing to use

The 1st-fret shape puts F in the bass for a root-position sound. The Fdim/A♭ inversion at the 4th fret places A♭ in the bass, which softens the chord's bite.

Other F chords

Common questions

How do I write F diminished?

Write F° or Fdim. The root is F, and the chord is spelled F–A♭–C♭.

Why does F diminished sound unstable?

The ♭5 interval creates a tritone with the root, which wants to resolve. This tension is what gives diminished chords their forward drive.

Can I use F diminished in place of F minor?

Only when you want that darker, more dissonant color. F diminished lowers the fifth, so it clashes with melodies that expect the perfect fifth C.