C dominant ninth (C9) chord on piano

The C dominant ninth chord (C9) is a dominant ninth chord (a dominant seventh plus a major ninth), made of five notes: C – E – G – B♭ – D.

Full chord: C4 – E4 – G4 – B♭4 – D5

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What the C9 chord sounds like

A dominant ninth is a dominant seventh with an added major ninth. A fuller, fatter dominant sound – a staple of funk, soul and blues.

Notes of the C9 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)

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

C4 – E4 – G4 – B♭4 – D5

Two-hand voicing

C3 – E4 – B♭4 – D5 – G5

Which keys is it in?

The C9 chord is built from the notes of these keys (for minor keys, both the natural and the harmonic minor are considered):

F major: V9 (dominant)
D minor: VII9

Similar chords and substitutes

If C9 is too hard, or you want a different colour in the same spot, these chords are worth a try.

Substitutes (by function)

F♯7 – tritone substitute: the same third and seventh, swapped – a jazz favourite
Edim7 – diminished seventh on the third: a common stand-in for the dominant
C7 – a simpler dominant
C7sus4 – suspended dominant, less tense
F – where it resolves (V → I)

Simpler versions

C7 – all 4 of its notes are in this chord
Cadd9 – all 4 of its notes are in this chord
C – all 3 of its notes are in this chord
Csus2 – all 3 of its notes are in this chord

Richer versions

C11 – the same chord plus 1 colour note
C13 – the same chord plus 1 colour note

Frequently asked questions

What notes are in the C9 chord?

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

How do I play the C9 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 5 notes in one hand is possible but sounds crowded.

How is the C9 chord written?

The chord symbol is C9, and its full name is C dominant ninth.