C7 (C7)

A dominant seventh chord: a major chord with an added minor seventh. It creates tension that pulls toward the next chord.

It’s played in open position, near the nut, and as a barre chord higher up the neck. It pulls toward F major: you hear it right before the return home in songs in F major, and all over the blues.

Notes:: C, E, G, B♭.
Formula:: 1, 3, 5, ♭7.
Difficulty:: Beginner.
Strings played:: 5 (from the A string).

Chord diagram

e|--0--|
B|--1--|
G|--3--|
D|--2--|
A|--3--|
E|--x--|

Other positions

e|--3--|
B|--5--|
G|--3--|
D|--5--|
A|--3--|
E|--x--|

e|--8---|
B|--8---|
G|--9---|
D|--8---|
A|--10--|
E|--8---|

Often played with

The chords in its key, the ones you hear most often around C7.

e|--1--|
B|--1--|
G|--2--|
D|--3--|
A|--3--|
E|--1--|

F majorresolution

e|--1--|
B|--3--|
G|--3--|
D|--3--|
A|--1--|
E|--x--|

B♭ majorIV of the key

e|--3--|
B|--3--|
G|--3--|
D|--5--|
A|--5--|
E|--3--|

G minorii of the key