Asus4

Q: What notes are in the Asus4 chord?

The Asus4 chord (A Sus4) contains: A, D, E. Its interval structure is shown above in the Theory section.

Q: How do I build Asus4 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 Asus4 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 Asus4?

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.

A Sus4

Octaves

Musical context

ChordAsus4A Sus4

ArpeggioA majorBroken triad

ScaleA major7 notes

KeyA majorMajor key

ProgressionPop axisSequence

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

Theory

General info

Full name: A Sus4
Symbol: Asus4
Root: A
Quality: Sus4

Chord notes

1Aroot

4Dperfect 4th

5Eperfect 5th

Functions & resolutions

Typical function in key: viRelative tonic (vi)C major
Stability / tension: Moderate tension — suspension awaits resolution
Most common resolutions: AA Major AmA Minor
Unstable degrees: 3C#
4D
resolves down to the 3rd
Main resolution: Asus4source
AA Major
The suspended 4th in Asus4 pulls down to the 3rd, resolving to A major or minor.
Other resolutions: Asus4source
Deceptive resolution
AmA Minor
Asus4 can resolve to minor instead of major — the 4th drops to the minor 3rd.
Asus4source
No resolution needed
In modal music, a sus chord may remain an independent sonority without 4–3 or 2–3 motion; with no 3rd, it defines neither major nor minor quality.
Asus4source
Jazz reharmonization
A7sus4A 7sus4
In jazz, 7sus4 may retain its dominant bass and minor 7th without immediately resolving the 4th to the 3rd; it may also move to another sus chord.
Asus4source
Functional resolution
DD Major
A sus chord can move up a 4th or down a step, functioning as a suspension from degrees other than the tonic.

Features

Character: No 3rd, with 4th-degree tension
Characteristic interval: Fourth instead of 3rd (4)
Description: The 4th replaces the 3rd, so the chord defines neither major nor minor quality. In a typical sus4 resolution, the 4th descends to the 3rd.
Application: Pop and rock (sus4 → major)
Pause before resolution
Building tension

Voicing & structure

Root position

v1A(A4)Bass

root

v2D(D5)P4from A

v3E(E5)M2from D

Harmony

Compatible scales

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

ScaleD Major pentatonic ScaleD Yo (Japanese)ScaleD Akebono (Japanese)ScaleD Hirajoshi (Japanese)ScaleE Minor pentatonic ScaleE Iwato (Japanese)ScaleA Minor pentatonic ScaleA In (Japanese)ScaleA Yo (Japanese)ScaleC Major pentatonic

This chord on guitar 🎸

See how Asus4 looks on guitar.

Explore

Circle of fifths

Highlighted major keys contain this chord among their diatonic harmonies.

Relative key: F#mF# minor
Dominant: EE major
Subdominant: DD major
Key signature: 3 sharps (F#, C#, G#)

What to learn next

ScaleA Ionian (major)Scale to improvise over this chord ChordA MajorA nearby chord on the same root — compare the sound PracticeChord trainerLock the fingering into muscle memory ProgressionChord progressionsHow this chord works inside real progressions ChordA Sus2Another related chord to practise

Recommended for you

A MajorA chord that sounds close

A Sus2A chord that sounds close

A 7sus4A chord that sounds close

A Ionian (major)A scale related to this chord

A DorianA 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 Asus4 chord?

How do I build Asus4 on the keyboard?

Which keys is Asus4 found in?

What can I substitute for Asus4?