B9sus4

Q: What notes are in the B9sus4 chord?

The B9sus4 chord (B 9sus4) contains: B, E, F#, A, C#. Its interval structure is shown above in the Theory section.

Q: How do I build B9sus4 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 B9sus4 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 B9sus4?

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 9sus4

Octaves

Musical context

ChordB9sus4B 9sus4

ArpeggioB majorBroken triad

ScaleB major7 notes

KeyB majorMajor key

ProgressionPop axisSequence

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

Theory

General info

Full name: B 9sus4
Symbol: B9sus4
Root: B
Quality: 9sus4

Chord notes

1Broot

4Eperfect 4th

5F#perfect 5th

b7Aminor 7th

2C#major 2nd

Functions & resolutions

Typical function in key: viRelative tonic (vi)D major
Stability / tension: Stable — can serve as major tonic
Most common resolutions: EE Major F#F# Major G#mG# Minor
Unstable degrees: 4E
b7A
resolves down to the resolution tonic
Main resolution: B9sus4source
F#F# Major
Major chord B is a stable tonic. As tonic it doesn't require resolution, but in a progression context typically moves to IV or V.
Other resolutions: B9sus4source
Deceptive resolution
G#mG# Minor
As the V degree, a major chord can defy expectations by moving to vi instead of I (deceptive cadence).
B9sus4source
Modal resolution
AA Major
In modal context, a major chord can freely move to bVII, bIII, or bVI — characteristic of Mixolydian mode.
B9sus4source
Jazz reharmonization
Bmaj7B Major 7
In jazz, a major chord is enriched to maj7, 6/9, or add9 and can smoothly transition into a ii-V of another key (modulation).
B9sus4source
Functional resolution
F#F# Major
As the IV degree (subdominant), a major chord can resolve to V or directly to I (plagal cadence).

Features

Character: Dominant, with 4th and 9th but no 3rd
Characteristic interval: 4th instead of 3rd (4), Minor 7th (b7), Major 9th (9)
Description: The 4th replaces the 3rd, the minor 7th preserves dominant colour, and the 9th extends the sonority. With no 3rd, chord quality remains undefined until resolution.
Application: Dominant suspensions
Modal jazz
Funk and soul

Voicing & structure

Root position

v1B(B4)Bass

root

v2E(E5)P4from B

v3F#(F#5)M2from E

v4A(A5)m3from F#

v5C#(C#6)M3from A

Harmony

Compatible scales

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

ScaleE Yo (Japanese)ScaleF# Minor pentatonic ScaleA Major pentatonic ScaleF# Blues scale ScaleC# Phrygian ScaleC# Aeolian (natural minor)ScaleC# Locrian ScaleE Ionian (major)ScaleE Dorian ScaleE Mixolydian

This chord on guitar 🎸

See how B9sus4 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 DorianScale to improvise over this chord PracticeChord trainerLock the fingering into muscle memory ProgressionChord progressionsHow this chord works inside real progressions

Recommended for you

B DorianA scale related to this chord

B MixolydianA scale related to this chord

B Aeolian (natural minor)A scale related to this chord

B Chromatic 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 B9sus4 chord?

How do I build B9sus4 on the keyboard?

Which keys is B9sus4 found in?

What can I substitute for B9sus4?