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New Released in April 2026

G Diminished Chord on Piano (Gdim)

G diminished (Gdim) is spelled G - Bb - Db: root, minor 3rd and diminished 5th. Its sound is tense, so it rarely stays long before moving on. Below: the keyboard, the three positions, how it compares with G and Gm, and where it goes next.

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Gdim G Bb Db

Four triads on G

Same root, same third or fifth moved by a semitone.

ChordNotesThirdFifth
G G B Dmajor 3rdperfect 5th
Gm G Bb Dminor 3rdperfect 5th
Gdim G Bb Dbminor 3rddiminished 5th
Gaug G B D#major 3rdaugmented 5th

Gdim in keys and progressions

  • Gdim is the vii° chord of Ab major and the ii° chord of F minor.
  • It wants to move up a semitone: Gdim → Ab / Abm, the bottom note rising to the new root.
  • Add F and you get Gm7b5 (half-diminished); add Fb instead and you get Gdim7 (diminished 7th).

Gm7b5 · Ab

The G diminished chord and its inversions

Any order of G, Bb, Db is still Gdim.

Gdim G Bb Db

Root position: G Bb Db

Gdim Bb Db G

1st inversion: Bb Db G

Gdim Db G Bb

2nd inversion: Db G Bb

  • Root position: starts on G, a white key; black keys: Bb, Db
  • 1st inversion: starts on Bb, a black key; black keys: Bb, Db
  • 2nd inversion: starts on Db, a black key; black keys: Db, Bb
ChordRunner showing a chord block while hands play the piano

Practise Gdim by playing

In ChordRunner Gdim rides towards your runner between other chords: play it in time. MIDI keyboard or microphone, both work.

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All piano chords · Diminished chords explained

Common questions

What notes are in the G diminished chord?

Gdim has three notes: G, Bb, Db. Root, minor 3rd and diminished 5th (formula 1 b3 b5).

What is the difference between Gdim and Gm?

One note. Gm has D on top; Gdim moves it to Db. The new fifth is what gives Gdim its tense sound.

Where does Gdim go?

Gdim is the vii° chord of Ab major and the ii° chord of F minor. It wants to move up a semitone: Gdim → Ab / Abm, the bottom note rising to the new root.

Can I practise Gdim with a MIDI keyboard or microphone?

Yes. ChordRunner detects a USB MIDI keyboard automatically and also hears an acoustic piano through the microphone. Gdim counts in any position, as long as G, Bb, Db sound together.

Your instrument is the controller.

ChordRunner is a browser game that teaches piano and guitar chords: a chord appears on screen, you play it on a real instrument, and your runner jumps. MIDI keyboard or microphone, both work.

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