7th chords add a fourth note on top of a triad. They create richer, more complex harmonies used throughout jazz, pop, and classical music.
Major 7th
[0, 4, 7, 11]
Minor 7th
[0, 3, 7, 10]
Dominant 7th
[0, 4, 7, 10]
Minor 7th (b5)
[0, 3, 6, 10]
Diminished 7th
[0, 3, 6, 9]
CMaj7
Notes: C – E – G – B
Chord Tones
C
Root
E
Major 3rd
G
Perfect 5th
B