Usually you can find size numbers printed on the interiors of the temple arm. You can find some numbers, like this: 57 16 145 or 57-16-145. The first 2-digit number means lens width, the second 2-digit number means bridge width, the 3-digit number means temple length.

To know how well a pair will fit you, we recommend you compare the measurements of your current glasses to the frame sizes mentioned on our product pages.