C♯aug7: C♯/D♭ Augmented 7th Piano Chord

Root position: either hand, fingers low note to high
Hand	Notes	Fingers
Right	C♯, E♯, G×, B	2-3-4-5
Left	C♯, E♯, G×, B	5-4-3-2

Scale degree, note, and interval measured from the root.
Degree	Note	Interval from root	Semitones
1	C♯	Perfect unison	0
3	E♯	Major third	4
♯5	G×	Minor sixth	8
♭7	B	Minor seventh	10

Construction

C♯ Augmented 7th = Root + Major 3rd + Minor 6th + Minor 7th = C♯, E♯, G♯♯, B

Note	Interval	Degree
C♯	Root	1
E♯	Major 3rd	3
G♯♯	Minor 6th	♯5
B	Minor 7th	♭7

Fingering

Note	Key color	Right hand	Left hand
C♯	black	index finger (2)	little finger (5)
E♯	white	middle finger (3)	ring finger (4)
G♯♯	white	ring finger (4)	middle finger (3)
B	white	little finger (5)	index finger (2)

Right hand: index finger (2) on C♯, middle finger (3) on E♯, ring finger (4) on G♯♯, little finger (5) on B.

Left hand: little finger (5) on C♯, ring finger (4) on E♯, middle finger (3) on G♯♯, index finger (2) on B.

C♯ Augmented 7th Inversions

Root position
C♯ – E♯ – G♯♯ – B
1st inversion (C♯aug7/E♯)
E♯ – G♯♯ – B – C♯
2nd inversion (C♯aug7/G♯♯)
G♯♯ – B – C♯ – E♯
3rd inversion (C♯aug7/B)
B – C♯ – E♯ – G♯♯

Key Signature

A Augmented 7th 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 C♯ Major

These are the triads built on each degree of C♯ Major:

I — C♯ Major (major)

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

Same Notes, Other Names

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

C♯ 7♯5→

C♯ Augmented 7th : Frequently Asked Questions

What is the C♯ Augmented 7th chord on piano?

The C♯ Augmented 7th chord contains the notes C♯ – E♯ – G♯♯ – B. On piano, play these notes together to sound the chord.

What is the C# piano chord?

The C# piano chord (written C♯ Augmented 7th) uses the same keys: C♯ – E♯ – G♯♯ – B. The # and ♯ symbols name the same black key.

What notes are in the C# Augmented 7th chord?

C# Augmented 7th is built from the C# root. Check the interactive keyboard above for exact notes and fingering.

How is the C# Augmented 7th chord used in music?

C# Augmented 7th appears in jazz, pop, and classical contexts. Its sound depends on the chord quality (Augmented 7th).

What is the fingering for C# Augmented 7th?

See the fingering chart above. Right hand typically uses thumb on root. Left hand uses pinky on root.

What are the inversions of C# Augmented 7th?

Use the inversion buttons above to see each inversion with notes, fingering, and staff notation.

C♯ Augmented 7th 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	C♯3 E♯3 G×3 B3	10	138 mm	none	identical
Close, first inversion	E♯3 G×3 B3 C♯4	8	110 mm	none	identical
Close, second inversion	G×3 B3 C♯4 E♯4	8	110 mm	none	identical
Close, third inversion	B3 C♯4 E♯4 G×4	10	138 mm	none	identical
Drop 2	G×2 C♯3 E♯3 B3	14	193 mm	none	identical
Drop 3	E♯2 C♯3 G×3 B3	18	248 mm	none	identical
Drop 2 and 4	C♯2 G×2 E♯3 B3	22	303 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
Shell, root ♭7 3	C♯2 B2 E♯3	16	220 mm	omits G×	subset
Guide tones, 3 and ♭7	E♯3 B3	6	83 mm	omits C♯ and G×	subset
Rootless close	E♯3 G×3 B3	6	83 mm	omits C♯	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	C♯	C♯3, E♯3, G×3, B3	7	10	138 mm
First inversion: C♯aug7/E♯	E♯	E♯3, G×3, B3, C♯4	6/5	8	110 mm
Second inversion: C♯aug7/G×	G×	G×3, B3, C♯4, E♯4	4/3	8	110 mm
Third inversion: C♯aug7/B	B	B3, C♯4, E♯4, G×4	4/2	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
C♯aug	drops B	1 3 ♯5	3
C♯7	G× becomes G♯	1 3 5 ♭7	3
C♯9	G× becomes G♯, D♯	1 3 5 ♭7 9	3
C♯	G×, B becomes G♯	1 3 5	2
C♯maj7	G×, B becomes G♯, B♯	1 3 5 7	2
C♯m7	E♯, G× becomes E, G♯	1 ♭3 5 ♭7	2
C♯m7♭5	E♯, G× becomes E, G	1 ♭3 ♭5 ♭7	2
C♯7sus4	E♯, G× becomes F♯, G♯	1 4 5 ♭7	2
C♯6	G×, B becomes G♯, A♯	1 3 5 6	2
C♯add9	G×, B becomes G♯, D♯	1 3 5 9	2

Frequencies

Note	MIDI	Frequency
C♯3	49	138.59 Hz
E♯3	53	174.61 Hz
G×3	57	220.00 Hz
B3	59	246.94 Hz

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

Set theory: prime form, Forte number, interval vector

Absolute pitch class set: {1, 5, 9, 11}
Normal order: [9, 11, 1, 5]
Prime form: (0248)
Forte number: 4-24
Interval vector: <020301>

Pair	Interval	Semitones	Interval class
C♯ to E♯	Major third	4	4
C♯ to G×	Minor sixth	8	4
C♯ to B	Minor seventh	10	2
E♯ to G×	Major third	4	4
E♯ to B	Tritone	6	6
G× to B	Major second	2	2

Where these facts come from

Every value on this page is derived from the note formula for a augmented 7th applied to the root C♯, 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.

C♯ Augmented 7th

Fingerings

C♯ Augmented 7th: notes and degrees