Tools / Chords / A diminished 7th

A diminished 7th chord on bass (Adim7)

Also written Adim7 or A°7

A diminished 7th contains A, C, E♭, and G♭. The 4th fret position demands a wide pinky stretch across all four strings.

4th fret5-6-4-5

Positions on the neck1 of 5

How it’s built

A1Root

C♭3Minor 3rd

E♭♭5Diminished 5th

G♭♭♭7Minor 7th

Formula 1, ♭3, ♭5, ♭♭7

Positions on the neck1 of 5

Inversions

The same three notes, with a different one in the bass.

Root positionA–C–E♭–G♭Adim7Bass A

First inversionC–E♭–G♭–AAdim7/CBass C

Second inversionE♭–G♭–A–CAdim7/E♭Bass E♭

Third inversionG♭–A–C–E♭Adim7/G♭Bass G♭

Why it sounds like that

A diminished 7th is built from the formula 1, ♭3, ♭5, ♭♭7. The diminished 5th between A and E♭ gives the chord its tense quality. Compare it to A minor 7th flat 5th, which raises the ♭♭7 to a ♭7.

What goes wrong with A diminished 7th?

Letting the pinky flatten and buzz the 3rd string.
Pressing the index finger too hard, sharpening the 2nd string note.

When to use it

A diminished 7th works as a passing chord in minor keys, often resolving to B minor or B major. Use it in jazz, classical, and metal bass lines for a dark, unstable color. It also pairs with A minor 7th flat 5th in half-diminished contexts.

Changing to and from A diminished 7th

Slide the shape down two frets to the 2nd fret to reach G diminished 7th.
Slide the shape up one fret to the 5th fret to reach B♭ diminished 7th.

Which voicing to use

The 4th fret position puts the root A on the E string, giving a solid low foundation. For a higher, thinner sound, use the Adim7/C inversion at the 7th fret, where C is the lowest note.

How do you play an A diminished 7th chord on bass?

4th fret

Intermediate● On the diagram

A diminished 7th is played at the 4th fret as 5 6 4 5: middle finger on the E string at fret 5, pinky finger on the A string at fret 6, index finger on the D string at fret 4 and ring finger on the G string at fret 5.

Tip — The pinky must reach the 6th fret on the A string while the ring finger holds the 5th fret on the G string, stretching the hand.

String-by-string breakdown

String	Fret	Finger	Note
4 (E)	5	2	A (1)
3 (A)	6	4	E♭ (♭5)
2 (D)	4	1	G♭ (♭♭7)
1 (G)	5	3	C (♭3)

Adim7/C inversion

Intermediate

A diminished 7th is played at the 7th fret as 8 9 7 8: middle finger on the E string at fret 8, pinky finger on the A string at fret 9, index finger on the D string at fret 7 and ring finger on the G string at fret 8.

String-by-string breakdown

String	Fret	Finger	Note
4 (E)	8	2	C (♭3)
3 (A)	9	4	G♭ (♭♭7)
2 (D)	7	1	A (1)
1 (G)	8	3	E♭ (♭5)

Adim7/E♭ inversion

Intermediate

A diminished 7th is played at the 10th fret as 11 12 10 11: middle finger on the E string at fret 11, pinky finger on the A string at fret 12, index finger on the D string at fret 10 and ring finger on the G string at fret 11.

String-by-string breakdown

String	Fret	Finger	Note
4 (E)	11	2	E♭ (♭5)
3 (A)	12	4	A (1)
2 (D)	10	1	C (♭3)
1 (G)	11	3	G♭ (♭♭7)

Adim7/G♭ inversion · fret 1

Intermediate

A diminished 7th is played at the 1st fret as 2 3 1 2: middle finger on the E string at fret 2, pinky finger on the A string at fret 3, index finger on the D string at fret 1 and ring finger on the G string at fret 2.

String-by-string breakdown

String	Fret	Finger	Note
4 (E)	2	2	G♭ (♭♭7)
3 (A)	3	4	C (♭3)
2 (D)	1	1	E♭ (♭5)
1 (G)	2	3	A (1)

Adim7/G♭ inversion · fret 13

Intermediate

A diminished 7th is played at the 13th fret as 14 15 13 14: middle finger on the E string at fret 14, pinky finger on the A string at fret 15, index finger on the D string at fret 13 and ring finger on the G string at fret 14.

String-by-string breakdown

String	Fret	Finger	Note
4 (E)	14	2	G♭ (♭♭7)
3 (A)	15	4	C (♭3)
2 (D)	13	1	E♭ (♭5)
1 (G)	14	3	A (1)

Common questions

How is A diminished 7th written?

A diminished 7th is written as A°7 or Adim7.

What is the difference between A diminished 7th and A minor 7th flat 5th?

A diminished 7th has a ♭♭7 (G♭), while A minor 7th flat 5th has a ♭7 (G). The diminished 7th is more dissonant and symmetrical.

Can A diminished 7th be played in open position?

No, A diminished 7th has no open strings in any of its standard positions. The lowest position starts at the 1st fret for the G♭ inversion.

String

Fret

Finger

Note

4 (E)

A (1)

3 (A)

E♭ (♭5)

2 (D)

G♭ (♭♭7)

1 (G)

C (♭3)

String

Fret

Finger

Note

4 (E)

C (♭3)

3 (A)

G♭ (♭♭7)

2 (D)

A (1)

1 (G)

E♭ (♭5)

String

Fret

Finger

Note

4 (E)

E♭ (♭5)

3 (A)

A (1)

2 (D)

C (♭3)

1 (G)

G♭ (♭♭7)

String

Fret

Finger

Note

4 (E)

G♭ (♭♭7)

3 (A)

C (♭3)

2 (D)

E♭ (♭5)

1 (G)

A (1)

String

Fret

Finger

Note

4 (E)

G♭ (♭♭7)

3 (A)

C (♭3)

2 (D)

E♭ (♭5)

1 (G)

A (1)