A suspended fourth chord (Asus4)
The A suspended fourth chord (Asus4) is a suspended chord: A, D and E (root, perfect fourth and perfect fifth). It has no third, so it is neither major nor minor.
It is the Isus4 in A major and the Vsus4 in D major, and it usually resolves to the major or minor chord on the same root.
Below: voicings, notes on the fretboard, ukulele, piano, inversions and progressions.
How to play A suspended fourth on guitar
There are 3 guitar voicings.
Frets from the 6th string to the 1st: x = not played, 0 = open string.
- Voicing 1: x-0-2-2-3-0, barre at fret 2, with A in the bass (fingers x-0-1-1-2-0).
- Voicing 2: 5-7-7-7-5-5, movable E-shape barre chord at fret 5, with A in the bass.
- Voicing 3: x-12-14-14-15-12, movable A-shape barre chord at fret 12, with A in the bass.
Notes of the A suspended fourth chord on the fretboard
A suspended fourth has 3 notes: A, D and E. This is where they fall on each string, from the nut to the 12th fret (fret number in parentheses):
- String 6 (E): E (0) · A (5) · D (10) · E (12)
- String 5 (A): A (0) · D (5) · E (7) · A (12)
- String 4 (D): D (0) · E (2) · A (7) · D (12)
- String 3 (G): A (2) · D (7) · E (9)
- String 2 (B): D (3) · E (5) · A (10)
- String 1 (E): E (0) · A (5) · D (10) · E (12)
Formula and intervals of A suspended fourth
Its formula is 1-4-5; in semitones from the root, 0-5-7.
- A: Root, the note that gives the chord its name
- D: Perfect fourth (P4), 5 semitones above A
- E: Perfect fifth (P5), 7 semitones above A
A suspended fourth on ukulele
- Ukulele (G C E A): 2-2-0-0; it sounds A, D, E and A.
A suspended fourth on piano
- Keys: A4, D5 and E5.
Inversions of A suspended fourth
Each inversion puts a different note in the bass.
- Root position: A, D and E, with A in the bass.
- First inversion (Asus4/D): D, E and A, with D in the bass.
- Second inversion (Asus4/E): E, A and D, with E in the bass.
Keys that use A suspended fourth
A suspended fourth appears in 10 major and minor keys.
| Key | Degree | Function |
|---|---|---|
| A major (3 sharps) | Isus4 | Tonic |
| G major (1 sharp) | IIsus4 | Supertonic |
| F major (1 flat) | IIIsus4 | Mediant |
| D major (2 sharps) | Vsus4 | Dominant |
| C major (no sharps or flats) | VIsus4 | Submediant |
| A minor (no sharps or flats) | Isus4 | Tonic |
| F♯ minor (3 sharps) | IIIsus4 | Mediant |
| E minor (1 sharp) | IVsus4 | Subdominant |
| D minor (1 flat) | Vsus4 | Dominant |
| B minor (2 sharps) | VIIsus4 | Subtonic |
Progressions with A suspended fourth
- Sus4 resolution in A major (Isus4–I): Asus4 – A
Frequently asked questions
What notes are in the A suspended fourth chord?
A, D and E: root, perfect fourth and perfect fifth. Its formula is 1-4-5.
Which keys use A suspended fourth?
Mainly as the Isus4 in A major and the Vsus4 in D major. In total it appears in 10 major and minor keys.
What does “sus” mean in A suspended fourth?
That the chord is suspended: the third is replaced by another note, leaving A, D and E (root, perfect fourth and perfect fifth). Without a third, it can move to either the major or the minor triad on the same root.