What Do the Numbers on Sunglasses Mean? Frame Sizes Explained

Inside the arm or on the bridge of most frames you will find numbers such as 52-18 140. They tell you how the frame will fit.

The three numbers

Lens width (52): the width of one lens in millimetres.
Bridge width (18): the gap between the lenses, where the frame sits on the nose.
Temple length (140): the length of the arm from hinge to tip.

How to use them

Find a pair you already own that fits well and read its numbers. A new frame within two millimetres of those figures will fit in much the same way.

Lens width under 50: small.
50 to 54: medium.
55 and over: large or oversized.

Vintage frames

Older frames, especially from the 1950s and 1960s, often run smaller than modern ones and are not always marked. In that case measure the full width of the frame front from hinge to hinge and compare it with a pair you own.