Bdim7

Q: What notes are in the Bdim7 chord?

The Bdim7 chord (B Diminished 7th) contains: B, D, F, Ab. Its interval structure is shown above in the Theory section.

Q: How do I build Bdim7 on the keyboard?

Take the root and add the remaining chord tones following the interval formula. The highlight shows chord content, while the inversion control changes which chord tone is in the bass.

Q: Which keys is Bdim7 found in?

The chord acts as a diatonic degree in several keys — they are marked on the circle of fifths in the "Harmonic context" block.

Q: What can I substitute for Bdim7?

A substitution depends on harmonic function and voice leading, not only on shared tones. Computed options appear in the "Substitutions" block and should be checked in context.

B Diminished 7th

Octaves

Musical context

ChordBdimTriad

ChordBdim7B Diminished 7th

ArpeggioB minorBroken triad

ScaleB minor7 notes

KeyB minorMinor key

ProgressionAndalusianSequence

How the chord relates to the scale, mode, key and progression.

Theory

General info

Full name: B Diminished 7th
Symbol: Bdim7
Root: B
Quality: Diminished 7th

Chord notes

1Broot

b3Dminor 3rd

b5Fdim 5th

bb7Abdim 7th

Functions & resolutions

Stability / tension: Maximum tension — extremely unstable
Most common resolutions: CC Major D#D# Major
Unstable degrees: 2C#
b3D
resolves down to the 2nd
4E
b5F
resolves inward to the 4th
b6G
bb7G#
resolves down to the tonic 5th
Main resolution: Bdim7source
CC Major
Diminished Bdim acts as a leading-tone chord — resolves up a half step to C. All tones are unstable, moving by semitones inward and outward to stable degrees.
Other resolutions: Bdim7source
Deceptive resolution
D#D# Major
Due to its symmetry, a diminished 7th chord can resolve to any major or minor chord a minor 3rd apart.
Bdim7source
Modal resolution
C#mC# Minor
In modal context, a diminished chord can be used as a passing chord, connecting two diatonic chords through chromatic bass motion.
Bdim7source
Jazz reharmonization
A#7A# Dominant 7
In jazz, dim7 is often reinterpreted as a rootless dominant 7b9. For example, Bdim7 ≈ A#7b9, opening additional resolution paths.
Bdim7source
Functional resolution
F#mF# Minor
A diminished chord can function as a leading-tone chord to any degree — not just the tonic. Often used before the ii, iii, or vi degrees.

Features

Character: Fully diminished, symmetric and unstable
Characteristic interval: Diminished 7th (°7)
Description: Four tones are stacked in minor 3rds; the diminished 5th and 7th create two tritones. Symmetry allows any tone to be enharmonically reinterpreted as the root.
Application: Leading-tone seventh in minor
Secondary leading-tone chords
Chromatic voice leading

Voicing & structure

Root position

v1B(B4)Bass

root

v2D(D5)m3from B

v3F(F5)m3from D

v4Ab(Ab5)m3from F

Harmony

Compatible scales

All chord tones are contained in these scales — use them for improvisation.

ScaleD Romanian minor ScaleD Ukrainian Dorian ScaleF Romanian minor ScaleF Ukrainian Dorian ScaleG# Romanian minor ScaleG# Ukrainian Dorian ScaleB Romanian minor ScaleB Ukrainian Dorian ScaleC Harmonic minor ScaleC Harmonic major

This chord on guitar 🎸

See how Bdim7 looks on guitar.

Explore

Circle of fifths

Highlighted major keys contain this chord among their diatonic harmonies.

Relative key: G#mG# minor
Dominant: F#F# major
Subdominant: EE major
Key signature: 5 sharps (F#, C#, G#, D#, A#)

What to learn next

ScaleB Chromatic scaleScale to improvise over this chord ChordB DiminishedA nearby chord on the same root — compare the sound PracticeChord trainerLock the fingering into muscle memory ProgressionChord progressionsHow this chord works inside real progressions ChordB Half-dim 7Another related chord to practise

Recommended for you

B DiminishedA chord that sounds close

B Half-dim 7A chord that sounds close

B Chromatic scaleA scale related to this chord

B Diminished scaleA scale related to this chord

Practice

Keyboard Trainer

Reinforce it in practice — play and name notes on the interactive keyboard.

Open Trainer

Test yourself

(Press any key to start)

What notes are in the Bdim7 chord?

How do I build Bdim7 on the keyboard?

Which keys is Bdim7 found in?

What can I substitute for Bdim7?