C add9 (Cadd9) chord on piano

The C add9 chord (Cadd9) is an add9 chord (a major triad plus a major ninth, no seventh), made of four notes: C – E – G – D.

Root position: C4 – E4 – G4 – D5

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What the Cadd9 chord sounds like

An add9 chord is a major triad with an added ninth and no seventh. It sounds bright and shimmering – a favourite colour in acoustic pop.

Notes of the Cadd9 chord

Degree	Note	Interval from the root
1	C	root
3	E	major third (4 semitones)
5	G	perfect fifth (7 semitones)
9	D	major second (2 semitones)

Root position and inversions

An inversion uses the same notes, with a different note at the bottom. When you change chords, choosing the nearest inversion keeps your hand almost still.

Root position

C4 – E4 – G4 – D5

1st inversion

E4 – G4 – D5 – C5

2nd inversion

G4 – D5 – C5 – E5

3rd inversion

D5 – C5 – E5 – G5

Which keys is it in?

The Cadd9 chord is built from the notes of these keys (for minor keys, both the natural and the harmonic minor are considered):

C major: Iadd9 (tonic)
F major: Vadd9 (dominant)
G major: IVadd9 (subdominant)
D minor: VIIadd9
A minor: IIIadd9
E minor: VIadd9

Similar chords and substitutes

If Cadd9 is too hard, or you want a different colour in the same spot, these chords are worth a try.

Substitutes (by function)

Am – relative minor: two shared notes, a common stand-in for the tonic
Em – mediant minor (iii): two shared notes
Cmaj7 – a softer, jazzier tonic colour
Csus4 – suspended version that resolves back to this chord

Simpler versions

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

Richer versions

C9 – the same chord plus 1 colour note
Cmaj9 – the same chord plus 1 colour note
C11 – the same chord plus 2 colour notes
C13 – the same chord plus 2 colour notes

Frequently asked questions

What notes are in the Cadd9 chord?

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

How do I play the Cadd9 chord on piano?

In root position, the right hand usually plays with fingers 1, 3 and 5 (thumb, middle finger, little finger); four-note chords with fingers 1, 2, 3 and 5. The left hand mirrors this: 5, 3, 1. In an inversion the top or bottom note moves to the other side, so your hand moves less when you change chords.

How is the Cadd9 chord written?

The chord symbol is Cadd9, and its full name is C add9.