A♯sus4: A♯/B♭ Suspended 4th Piano Chord

Root position: either hand, fingers low note to high
Hand	Notes	Fingers
Right	A♯, D♯, E♯	1-3-5
Left	A♯, D♯, E♯	5-3-1

Scale degree, note, and interval measured from the root.
Degree	Note	Interval from root	Semitones
1	A♯	Perfect unison	0
4	D♯	Perfect fourth	5
5	E♯	Perfect fifth	7

Construction

A♯ Suspended 4th = Root + Perfect 4th + Perfect 5th = A♯, D♯, E♯

Note	Interval	Degree
A♯	Root	1
D♯	Perfect 4th	4
E♯	Perfect 5th	5

Fingering

Note	Key color	Right hand	Left hand
A♯	black	thumb (1)	little finger (5)
D♯	black	middle finger (3)	middle finger (3)
E♯	white	little 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 (A♯sus4/D♯)
D♯ – E♯ – A♯
2nd inversion (A♯sus4/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:

I — A♯ Major (major)

Degree	Numeral	Chord	Quality
1	I	A♯ Major	Major
2	ii	B♯ Minor	Minor
3	iii	C♯♯ Minor	Minor
4	IV	D♯ Major	Major
5	V	E♯ Major	Major
6	vi	F♯♯ Minor	Minor
7	vii°	G♯♯ Diminished	Diminished

Scales That Include the A♯ Suspended 4th

F# Major (iii)
Db Major (vi)
Ab Major (ii)
Eb Major (V)
Bb Major (I)
G Minor (III)
C Minor (VII)
F Minor (iv)

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:

E♭ Suspended 2nd→

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 is the A# piano chord?

The A# piano chord (written A♯ Suspended 4th) uses the same keys: A♯ – D♯ – E♯. The # and ♯ symbols name the same black key.

What notes are in the A# Suspended 4th chord?

The A# Suspended 4th chord (A#sus4) 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 A#sus2?

Both replace the third, but A#sus2 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 A#sus4 → 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: A#sus4 → 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.

Type	Notes	Semitones	Span	Omissions and additions	Set relation
Close, root position	A♯3 D♯4 E♯4	7	96 mm	none	identical
Close, first inversion	D♯4 E♯4 A♯4	7	96 mm	none	identical
Close, second inversion	E♯4 A♯4 D♯5	10	138 mm	none	identical
Open, fifth on top	A♯2 E♯3 D♯4	17	234 mm	none	identical

Reduced

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

Type	Notes	Semitones	Span	Omissions and additions	Set relation	Fit
Root and third only	A♯3 D♯4	5	69 mm	omits E♯	subset

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

Position	Bass note	Notes in order	Figured bass	Semitones	Span
Root position	A♯	A♯3, D♯4, E♯4	5/3	7	96 mm
First inversion: A♯sus4/D♯	D♯	D♯4, E♯4, A♯4	6/3	7	96 mm
Second inversion: A♯sus4/E♯	E♯	E♯4, A♯4, D♯5	6/4	10	138 mm

One position per chord tone in the bass. Spans are for close position: voiced inversions appear under Voicings.

Change one note

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

Chord	Change	Formula	Common tones
A♯7sus4	adds G♯	1 4 5 ♭7	3
A♯	D♯ becomes C×	1 3 5	2
A♯m	D♯ becomes C♯	1 ♭3 5	2
A♯sus2	D♯ becomes B♯	1 2 5	2
A♯maj7	D♯ becomes C×, G×	1 3 5 7	2
A♯7	D♯ becomes C×, G♯	1 3 5 ♭7	2
A♯m7	D♯ becomes C♯, G♯	1 ♭3 5 ♭7	2
A♯mMaj7	D♯ becomes C♯, G×	1 ♭3 5 7	2
A♯6	D♯ becomes C×, F×	1 3 5 6	2
A♯m6	D♯ becomes C♯, F×	1 ♭3 5 6	2
A♯add9	D♯ becomes C×, B♯	1 3 5 9	2
A♯dim	D♯, E♯ becomes C♯, E	1 ♭3 ♭5	1

Frequencies

Note	MIDI	Frequency
A♯3	58	233.08 Hz
D♯4	63	311.13 Hz
E♯4	65	349.23 Hz

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

Set theory: prime form, Forte number, interval vector

Absolute pitch class set: {10, 3, 5}
Normal order: [3, 5, 10]
Prime form: (027)
Forte number: 3-9
Interval vector: <010020>

Pair	Interval	Semitones	Interval class
A♯ to D♯	Perfect fourth	5	5
A♯ to E♯	Perfect fifth	7	5
D♯ to E♯	Major second	2	2

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.

A♯ Suspended 4th

Fingerings

A♯ Suspended 4th: notes and degrees