Explore and Master the B Diminished Chord on Guitar

Bdim, the B diminished chord, is built from B, D and F. Bdim is the vii chord of C major, the diminished triad on the seventh degree.

A scale that covers every chord tone is the B whole-half scale, which is where to start when you improvise. The listed voicings run from fret 1 up to fret 14. The fretboard interval patterns in our theory guide show how note distances look across the strings.

Add one more minor third on top and the triad becomes a diminished seventh chord. Note names are labelled on the fretboard at the top of the page, which makes it easy to check the root and the other tones of each voicing.

B diminished guitar chord is also written as Bdim, B°, Bm(b5) or Bmb5.

Notes of the B dim chord:

B D F

How to create the Diminished chord:

Formula: 1 b3 b5

B Dim Chord Interactive Fretboard

Want a structured chord roadmap instead of jumping between pages?
Go to the full guitar chords tutorial.

B Dim Guitar Chord Diagrams

Position 1 Movable

Finger Positions

Mute the low E string
Mute the high E string
Place your index finger (1) on the fret 2 of the A string
Place your middle finger (2) on the fret 3 of the D string
Place your ring finger (3) on the fret 3 of the B string
Place your pinky finger (4) on the fret 4 of the G string

Position 2 Movable

Finger Positions

Mute the low E string
Mute the A string
Place your index finger (1) on the fret 6 of the B string
Place your middle finger (2) on the fret 7 of the high E string
Place your ring finger (3) on the fret 7 of the G string
Place your pinky finger (4) on the fret 9 of the D string

Position 3 Movable

Finger Positions

Mute the low E string
Mute the A string
Place your index finger (1) on the fret 9 of the D string
Place your middle finger (2) on the fret 10 of the G string
Place your ring finger (3) on the fret 10 of the high E string
Place your pinky finger (4) on the fret 12 of the B string

Position 4 Movable

Finger Positions

Mute the low E string
Mute the A string
Mute the D string
Place your index finger (1) on the fret 1 of the high E string
Place your middle finger (2) on the fret 3 of the B string
Place your ring finger (3) on the fret 4 of the G string

Position 5 Movable

Finger Positions

Mute the low E string
Mute the B string
Mute the high E string
Place your index finger (1) on the fret 10 of the G string
Place your middle finger (2) on the fret 12 of the D string
Place your pinky finger (4) on the fret 14 of the A string

Find more shapes in our all guitar chords online library. If you prefer a printable pdf, download the Free Guitar Chords Chart Pdf

Play This Chord With Other Roots

Keys With The B Diminished Chord

The most common place in which you'll find the B diminished chord is the 7th degree of the C major key:

Key	I	ii	iii	IV	V	vi	vii
C	C	Dm	Em	F	G	Am	B dim

Of course, B dim is also present in the relative minor key, A minor:

Key	i	ii	III	iv	v	VI	VII
A	Am	B dim	C	Dm	Em	F	G

Scales To Play Over a B Diminished Chord

The b3 and b5 in this chord make the locrian scale a great match, even if the overall sound will be a bit dissonant.

Other great matches are:

B Minor Blues Scale (the b5 is the Blue Note!)
B Dorian #4 Scale
B Whole Tone Scale

You can find a complete analysis of scales and chords relationship on my ebook Scales Over Chords | Learn How To Play The Right Scales Over Any Chord

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In the ebook you can also find maps show you the tones in a chord all along the fretboard. They are incredibly helpful because allow you to:

Create new voicings on the fly, across all the neck
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Created by

Giancarlo Facoetti

Giancarlo is a musician (teaching guitar since 2000), software engineer, AI consultant and published researcher

FAQ

Which notes form the Bdim chord?

Bdim contains B, D and F. That is the root, a minor third and a flat fifth. F is six semitones from B, a diminished fifth.

Why is the B diminished chord so common in C major?

In C major, Bdim is the vii chord, built on the seventh degree. B, D and F all belong to the key, and the chord resolves naturally toward C.

What changes between B minor and B diminished?

B minor has B, D and F#. Bdim lowers the F# to F, which removes the perfect fifth and introduces a tritone with the root.

Which scale covers Bdim?

The B Locrian scale, B, C, D, E, F, G, A, holds all three chord tones. Because it is the same set of notes as C major, it fits Bdim in that key.

How many Bdim voicings are there on guitar?

There are 5 voicings in total, none with open strings or a barre. The lowest is at fret 1 and the highest at fret 14.