Eyeglass Frame Size Calculator

About this calculator

Eyeglass frames are labeled with three numbers in millimeters — lens width, bridge width, and temple length — such as 52-18-140, and getting them right depends on your face width and pupillary distance (PD), the gap between the centers of your pupils. A frame that is too wide or too narrow shifts the optical center of the lens away from where your eyes actually look, causing eye strain or distortion.

Opticians and eyewear retailers size frames this way so that the lens’ optical center lines up with your pupils and the bridge sits comfortably on your nose. This calculator takes your face width and pupillary distance and recommends a matching lens width, bridge width, and total frame width.