Step 1: Locate the Measurements

Check the inside of the temple arms (the “arms” of your glasses). You’ll find three numbers engraved, usually in this format: 48-19-140. These numbers represent:

1. Lens Width: The horizontal width of each lens at its widest point (usually 40–60 mm)

2. Bridge Width: The distance between the two lenses, where the glasses rest on your nose (typically 14–24 mm)

3. Temple Length: The length of the arms from the hinge to the tip, including the bend that sits on your ear (commonly 120–150 mm)

Sometimes, a fourth number may appear, indicating Lens Height, which is important for bifocal or progressive lenses