C♯ eleventh (C♯11) chord on piano

Looking for the C♯11 chord on piano? It is an eleventh chord (a dominant ninth plus a perfect eleventh), made of six notes: C♯ – E♯ – G♯ – B – D♯ – F♯. The same chord with a different spelling: D♭ eleventh (D♭11).

Full chord: C♯4 – E♯4 – G♯4 – B4 – D♯5 – F♯5

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What the C♯11 chord sounds like

An eleventh chord has six notes in theory. In practice the third is left out (it clashes with the eleventh), so it sounds like a 9sus4 – a modern, open dominant.

Notes of the C♯11 chord

Degree	Note	Interval from the root
1	C♯	root
3	E♯	major third (4 semitones)
5	G♯	perfect fifth (7 semitones)
7	B	minor seventh (10 semitones)
9	D♯	major second (2 semitones)
11	F♯	perfect fourth (5 semitones)

Piano voicings

Chords with five or more notes are rarely played in one hand: the left hand takes the root, the right hand the colour notes. The fifth (and in an eleventh chord the third) is often left out.

Full chord

C♯4 – E♯4 – G♯4 – B4 – D♯5 – F♯5

Two-hand voicing

C♯3 – B4 – D♯5 – F♯5 – G♯5

Which keys is it in?

The C♯11 chord is built from the notes of these keys (for minor keys, both the natural and the harmonic minor are considered):

F♯ major: V11 (dominant)
D♯ minor: VII11

Similar chords and substitutes

If C♯11 is too hard, or you want a different colour in the same spot, these chords are worth a try.

Substitutes (by function)

G7 – tritone substitute: the same third and seventh, swapped – a jazz favourite
Fdim7 – diminished seventh on the third: a common stand-in for the dominant
C♯7 – a simpler dominant
C♯7sus4 – suspended dominant, less tense
F♯ – where it resolves (V → I)

Simpler versions

C♯9 – all 5 of its notes are in this chord
C♯7 – all 4 of its notes are in this chord
C♯7sus4 – all 4 of its notes are in this chord
C♯add9 – all 4 of its notes are in this chord

Frequently asked questions

What notes are in the C♯11 chord?

C♯, E♯, G♯, B, D♯, F♯. The root is C♯; the intervals of the other notes from the root: major third, perfect fifth, minor seventh, major second, perfect fourth.

How do I play the C♯11 chord on piano?

Play the root with your left hand and the colour notes (third, seventh, ninth) with your right hand – the two-hand voicing above. Stacking all 6 notes in one hand is possible but sounds crowded.

How is the C♯11 chord written?

The chord symbol is C♯11 (also written C#11), and its full name is C♯ eleventh.