semicord

Gadd9 G major add nine chord

Notes
G B D A
Formula
1 3 5 9
Semitones
0 4 7 14 above the root
Other symbols
G(add9), Gadd2

G to B is a major third (4 semitones), B to D is a minor third (3 semitones), D to A is a perfect fifth (7 semitones). A major triad with the ninth, A, added and no seventh. The ninth is the second of the scale an octave up, so with A played right next to the root the same chord is often written Gadd2. It is not Gsus2: the third B is still there.

Gadd9 on the piano

C4D4E4F4G4A4B4C5D5E5F5G5A5B5C#4Eb4F#4Ab4Bb4C#5Eb5F#5Ab5Bb5C4GBC5DA

Root position from G4: G4, B4, D5, A5. Middle C is C4.

Gadd9 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 G as its lowest note.

GGBBDAABGG
Open position
3 2 0 2 0 3 (low E to high e)
Sounds G2 B2 D3 A3 B3 G4
GGBB×AADD×
E-shape, root on the E string at fret 3
3 2 x 2 3 x (low E to high e)
Sounds G2 B2 A3 D4
9fr×GGBB×AADD
A-shape, root on the A string at fret 10
x 10 9 x 10 10 (low E to high e)
Sounds G3 B3 A4 D5

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 Gadd9

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 positionG B D AGadd9
1st inversionB D A GGadd9/B
2nd inversionD A G BGadd9/D
3rd inversionA G B DG/A (also read as Gadd9/A)

Where Gadd9 fits

Gadd9 is I in G major, IV in D major, V in C major. The added A belongs to all three of those keys, so Gadd9 can stand in for G wherever it appears; it keeps the major sound but softens it. It is not a substitute for G9, which also has the seventh F.