B-flat suspended fourth chord (Bbsus4)
The B♭ suspended fourth chord (B♭sus4) is a suspended chord: B♭, E♭ and F (root, perfect fourth and perfect fifth). It has no third, so it is neither major nor minor.
It is the Isus4 in B♭ major and the Vsus4 in E♭ 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 B♭ suspended fourth on guitar
There are 2 guitar voicings.
Frets from the 6th string to the 1st: x = not played, 0 = open string.
- Voicing 1: x-1-3-3-4-1, barre at fret 1, with B♭ in the bass (fingers x-1-2-3-4-1).
- Voicing 2: 6-8-8-8-6-6, movable E-shape barre chord at fret 6, with B♭ in the bass.
Notes of the B♭ suspended fourth chord on the fretboard
B♭ suspended fourth has 3 notes: B♭, E♭ and F. This is where they fall on each string, from the nut to the 12th fret (fret number in parentheses):
- String 6 (E): F (1) · B♭ (6) · E♭ (11)
- String 5 (A): B♭ (1) · E♭ (6) · F (8)
- String 4 (D): E♭ (1) · F (3) · B♭ (8)
- String 3 (G): B♭ (3) · E♭ (8) · F (10)
- String 2 (B): E♭ (4) · F (6) · B♭ (11)
- String 1 (E): F (1) · B♭ (6) · E♭ (11)
Formula and intervals of B♭ suspended fourth
Its formula is 1-4-5; in semitones from the root, 0-5-7.
- B♭: Root, the note that gives the chord its name
- E♭: Perfect fourth (P4), 5 semitones above B♭
- F: Perfect fifth (P5), 7 semitones above B♭
B♭ suspended fourth on ukulele
- Ukulele (G C E A): 3-3-1-1, barre at fret 1; it sounds B♭, E♭, F and B♭.
B♭ suspended fourth on piano
- Keys: B♭4, E♭5 and F5.
Inversions of B♭ suspended fourth
Each inversion puts a different note in the bass.
- Root position: B♭, E♭ and F, with B♭ in the bass.
- First inversion (B♭sus4/E♭): E♭, F and B♭, with E♭ in the bass.
- Second inversion (B♭sus4/F): F, B♭ and E♭, with F in the bass.
Keys that use B♭ suspended fourth
B♭ suspended fourth appears in 10 major and minor keys.
| Key | Degree | Function |
|---|---|---|
| B♭ major (2 flats) | Isus4 | Tonic |
| A♭ major (4 flats) | IIsus4 | Supertonic |
| G♭ major (6 flats) | IIIsus4 | Mediant |
| E♭ major (3 flats) | Vsus4 | Dominant |
| D♭ major (5 flats) | VIsus4 | Submediant |
| B♭ minor (5 flats) | Isus4 | Tonic |
| G minor (2 flats) | IIIsus4 | Mediant |
| F minor (4 flats) | IVsus4 | Subdominant |
| E♭ minor (6 flats) | Vsus4 | Dominant |
| C minor (3 flats) | VIIsus4 | Subtonic |
Progressions with B♭ suspended fourth
- Sus4 resolution in B♭ major (Isus4–I): B♭sus4 – B♭
B♭ suspended fourth or A♯ suspended fourth?
B♭ suspended fourth (B♭sus4) and A♯ suspended fourth (A♯sus4) are the same chord with two names: they sound the same and use the same frets.
The spelling depends on the key: it is written B♭ suspended fourth in flat keys and A♯ suspended fourth in sharp keys.
Frequently asked questions
What notes are in the B♭ suspended fourth chord?
B♭, E♭ and F: root, perfect fourth and perfect fifth. Its formula is 1-4-5.
Which keys use B♭ suspended fourth?
Mainly as the Isus4 in B♭ major and the Vsus4 in E♭ major. In total it appears in 10 major and minor keys.
Is A♯ suspended fourth the same chord as B♭ suspended fourth?
Yes: A♯ suspended fourth and B♭ suspended fourth sound the same and are played the same way. It is written B♭ suspended fourth in flat keys and A♯ suspended fourth in sharp keys.
What does “sus” mean in B♭ suspended fourth?
That the chord is suspended: the third is replaced by another note, leaving B♭, E♭ and F (root, perfect fourth and perfect fifth). Without a third, it can move to either the major or the minor triad on the same root.