semicord

Cmaj9 C major ninth chord

Notes
C E G B D
Formula
1 3 5 7 9
Semitones
0 4 7 11 14 above the root
Other symbols
CM9, CΔ9

C to E is a major third (4 semitones), E to G is a minor third (3 semitones), G to B is a major third (4 semitones), B to D is a minor third (3 semitones). A major seventh (Cmaj7) with the ninth, D, on top. The fifth, G, is often left out on guitar.

Cmaj9 on the piano

C4D4E4F4G4A4B4C5D5E5F5G5A5B5C#4Eb4F#4Ab4Bb4C#5Eb5F#5Ab5Bb5CC4EGBC5D

Root position from C4: C4, E4, G4, B4, D5. Middle C is C4.

Cmaj9 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.

×CCEEBBDD×
A-shape, root on the A string at fret 3
x 3 2 4 3 x (low E to high e)
Sounds C3 E3 B3 D4, fifth left out
7frCCEEBBDDGG×
E-shape, root on the E string at fret 8
8 7 9 7 8 x (low E to high e)
Sounds C3 E3 B3 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 ninth chords on other roots.

Inversions of Cmaj9

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 B DCmaj9
1st inversionE G B D CCmaj9/E
2nd inversionG B D C ECmaj9/G
3rd inversionB D C E GCmaj9/B
4th inversionD C E G BCmaj9/D

Where Cmaj9 fits

Cmaj9 is Imaj9 in C major, IVmaj9 in G major. Its upper four notes E G B D are Em7: play that chord over a C bass and you have Cmaj9.