The C major eleventh chord (abbreviated "Cmaj11 chord") is a six-note chord consisting of the notes C, E, G, B, D, and F. The chord is formed by adding an eleventh to a C major ninth chord.

In practice, the fifth (G) is often omitted from the Cmaj11 chord to avoid a very dissonant sound, and because it's not always possible to play all notes simultaneously.

Name
C major eleventh chord
Notes
C E G B D F
Intervals
1 3 5 7 9 11
Chord symbol
Cmaj11
Alternative symbols
C11 Cma11 CMA11 CM11
Type
Hexad (six-note chord)

Cmaj11 chord on piano

Cmaj11 chord on guitar

Cmaj11 chord on ukulele

Cmaj11 chord on the staff