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A Suspended 4th

Notes: A - D - E | Degrees: 1 - 4 - 5 | Written: Asus4, Asus

Construction: Root, Perfect 4th, Perfect 5th

It is a chord where the third is suspended and raised to the perfect fourth, giving it a tense, unresolved sound that naturally wants to resolve to the major third

Fingering: RH 1-3-5, LH 5-3-1

Inversions: Root Asus4 - 1st Asus4/D - 2nd Asus4/E

Related boards
First inversion7 st, 96.0 mmFigured bass: 6/3

D4, E4, A4

Fingerings

First inversion: either hand, fingers low note to high
HandNotesFingers
RightD, E, A1-2-5
LeftD, E, A5-4-1

Close-position standard fingering: either hand takes the whole shape. Thumb is 1, little finger is 5.

A Suspended 4th: notes and degrees

Asus4 contains A, D and E. The third replaced by the fourth.

Scale degree, note, and interval measured from the root.
DegreeNoteInterval from rootSemitones
1APerfect unison0
4DPerfect fourth5
5EPerfect fifth7

Every note is a white key.

Construction

A Suspended 4th = Root + Perfect 4th + Perfect 5th = A, D, E
NoteIntervalDegree
ARoot1
DPerfect 4th4
EPerfect 5th5

Fingering

NoteKey colorRight handLeft hand
Awhitethumb (1)little finger (5)
Dwhitemiddle finger (3)middle finger (3)
Ewhitelittle finger (5)thumb (1)

Right hand: thumb (1) on A, middle finger (3) on D, little finger (5) on E.

Left hand: little finger (5) on A, middle finger (3) on D, thumb (1) on E.

A Suspended 4th Inversions

  • Root position
    A – D – E
  • 1st inversion (Asus4/D)
    D – E – A
  • 2nd inversion (Asus4/E)
    E – A – D

Key Signature

A Suspended 4th chord is built from symmetrical or ambiguous intervals, so it doesn't belong to a single key and has no key signature of its own.

Chords in the Key of A Major

These are the triads built on each degree of A Major:

C1C2C3C4AC5EC6C7C8C♯
I — A Major (major)
DegreeNumeralChordQuality
1IA MajorMajor
2iiB MinorMinor
3iiiC♯ MinorMinor
4IVD MajorMajor
5VE MajorMajor
6viF♯ MinorMinor
7vii°G♯ DiminishedDiminished

Scales That Include the A Suspended 4th

Same Notes, Other Names

The notes A – D – E aren’t exclusive to this chord. Depending on which note is the bass and how the chord functions, the same pitches also spell:

A Suspended 4th : Frequently Asked Questions

What is the A Suspended 4th chord on piano?
The A Suspended 4th chord contains the notes A – D – E. On piano, play these notes together to sound the chord.
What notes are in the A Suspended 4th chord?
The A Suspended 4th chord (Asus4) contains: A (root), D (perfect fourth), and E (perfect fifth). The perfect fourth replaces the third, creating a strong upward pull toward resolution, the 4th degree (D) strongly wants to resolve down to the major third.
How does A Suspended 4th differ from Asus2?
Both replace the third, but Asus2 uses the 2nd degree (giving an airy, neutral feel) while A Suspended 4th uses the 4th degree (D), which creates stronger tension. The sus4 chord has a more urgent, directional pull toward resolution than sus2.
What does "sus4" resolve to?
The 4th degree (D) in a sus4 chord typically resolves down by one semitone to the major 3rd of the chord: this is the classical "suspension resolution." The movement D → (major 3rd) is one of the most satisfying motions in Western harmony and drives the resolution from Asus4 → A Major.
How is A Suspended 4th used in music?
Sus4 chords appear in nearly every genre. They create anticipation before resolution to a major chord, work as dramatic openings (Pinball Wizard, Hard Day's Night), and add harmonic colour in pop and classical music. The A Suspended 4th is especially common as a pre-dominant chord that builds tension before the final chord of a phrase.
What songs use suspended 4th chords?
A Hard Day's Night (Beatles) opens with a sus4 chord. Pinball Wizard (The Who) uses sus4 throughout. Feelin' Alright (Traffic), Behind Blue Eyes (The Who), and many hymns use sus4 chords for their characteristic build-and-release quality.
Can I use A Suspended 4th before A Major?
Yes: Asus4 → A Major is one of the most satisfying resolutions in music. The fourth degree (D) resolves down to the major third, while the root and fifth stay constant. This V–I style resolution works in any tempo and style, from gospel to pop to classical.

A Suspended 4th in detail

Exact

Every pitch class is present and nothing outside the chord is added.

TypeNotesSemitonesSpanOmissions and additionsSet relationFit
Close, root positionA3 D4 E4796 mmnoneidentical
Close, first inversionD4 E4 A4796 mmnoneidentical
Close, second inversionE4 A4 D510138 mmnoneidentical
Open, fifth on topA2 E3 D417234 mmnoneidentical

Reduced

A subset of the pitch classes: the identity is incomplete rather than altered.

TypeNotesSemitonesSpanOmissions and additionsSet relationFit
Root and third onlyA3 D4569 mmomits Esubset

Spans are measured centre to centre at a 165 mm octave (standard keyboard geometry).

Change one note

Chords a single note away, and what moving that note does.

ChordChangeFormulaCommon tones
A7sus4adds G1 4 5 ♭73
AD becomes C♯1 3 52
AmD becomes C1 ♭3 52
Asus2D becomes B1 2 52
Amaj7D becomes C♯, G♯1 3 5 72
A7D becomes C♯, G1 3 5 ♭72
Am7D becomes C, G1 ♭3 5 ♭72
AmMaj7D becomes C, G♯1 ♭3 5 72
A6D becomes C♯, F♯1 3 5 62
Am6D becomes C, F♯1 ♭3 5 62
Aadd9D becomes C♯, B1 3 5 92
AdimD, E becomes C, E♭1 ♭3 ♭51

Frequencies

NoteMIDIFrequency
A357220.00 Hz
D462293.66 Hz
E464329.63 Hz

Reference pitch A440, 12-TET, close root position.

Set theory: prime form, Forte number, interval vector
Absolute pitch class set
{9, 2, 4}
Normal order
[2, 4, 9]
Prime form
(027)
Forte number
3-9
Interval vector
<010020>
PairIntervalSemitonesInterval class
A to DPerfect fourth55
A to EPerfect fifth75
D to EMajor second22

Where these facts come from

Every value on this page is derived from the note formula for a suspended 4th applied to the root A, using standard music theory. Nothing here is hand-entered per chord, so the notes, intervals, inversions and frequencies cannot drift out of agreement with each other. Pitches assume 12-TET at A440.