How glasses sizing works

Every frame carries three numbers inside the arm \\u2014 lens width, bridge width, and temple length, in millimeters, like 52\\u25a118\\u2013145. The first two decide whether a frame sits correctly on your face; the third just needs to reach comfortably behind your ear. Match a pair you already like within a millimeter or two and online sizing stops being a guess. The full breakdown: how to read glasses frame size numbers.

Frame Size Finder FAQ

Which measurement matters most?

Lens width and bridge width together. They set how the frame balances on your nose and face. Total width should be close to your face width; temple length is the most forgiving of the three.

What if I am between two size bands?

Go by the fit of the frame front, not the arms. If your face width lands on a border, pick the smaller lens width \\u2014 frames that are slightly snug look intentional, while oversized ones slide down.

Do I still need to know my face shape?

Yes \\u2014 size is only half the fit. Shape decides how frames flatter you. Run the Frame Finder for shape, then use your size here to choose the exact pair.

Last updated: July 20, 2026 \\u00b7 Glasses Atlas Team \\u00b7 More free tools