semicord

Cadd9 C major add nine chord

Notes
C E G D
Formula
1 3 5 9
Semitones
0 4 7 14 above the root
Other symbols
C(add9), Cadd2

C to E is a major third (4 semitones), E to G is a minor third (3 semitones), G to D is a perfect fifth (7 semitones). A major triad with the ninth, D, added and no seventh. The ninth is the second of the scale an octave up, so with D played right next to the root the same chord is often written Cadd2. It is not Csus2: the third E is still there.

Cadd9 on the piano

C4D4E4F4G4A4B4C5D5E5F5G5A5B5C#4Eb4F#4Ab4Bb4C#5Eb5F#5Ab5Bb5CC4EGC5D

Root position from C4: C4, E4, G4, D5. Middle C is C4.

Cadd9 on the guitar

Standard tuning (E A D G B E). Strings run low E on the left to high e on the right, frets downwards; × is a muted string, ○ an open string, and each dot shows the note it sounds, with the root in blue-green. Every shape below has C as its lowest note.

×CCEEGDDE
Open position
x 3 2 0 3 0 (low E to high e)
Sounds C3 E3 G3 D4 E4
×CCEE×DDGG
A-shape, root on the A string at fret 3
x 3 2 x 3 3 (low E to high e)
Sounds C3 E3 D4 G4
7frCCEE×DDGG×
E-shape, root on the E string at fret 8
8 7 x 7 8 x (low E to high e)
Sounds C3 E3 D4 G4

The E-shape and A-shape grips are movable: an E-shape chord's root is the note under your first finger on the low E string, an A-shape chord's root is the note on the A string. Slide the same grip up or down to play major add nine chords on other roots.

Inversions of Cadd9

An inversion puts a note other than the root in the bass. The name is what semicord's chord finder calls those notes played bottom to top; a slash name like C/E means a C chord with E in the bass.

PositionNotes, bass firstNamedListen
Root positionC E G DCadd9
1st inversionE G D CCadd9/E
2nd inversionG D C ECadd9/G
3rd inversionD C E GC/D (also read as Cadd9/D)

Where Cadd9 fits

Cadd9 is I in C major, IV in G major, V in F major. The added D belongs to all three of those keys, so Cadd9 can stand in for C wherever it appears; it keeps the major sound but softens it. It is not a substitute for C9, which also has the seventh Bb.