The International 10-20 System

Odd numbers on the left, even on the right

z indicates midline electrodes

F = frontal

C = central

T = temporal

P = parietal

O = occipital

A1 and A2 are on the ears.

LC and RC are left and right cheek, respectively.

Dashed electrodes are optional.

Mouseover the image to see a variation on the naming scheme that is sometimes used.