Glasses & Frame Size Guide
Decode the 52▢18-140 numbers on your frames and find the lens width that suits your face.
Find your frame size
How to measure
The three numbers
On the arm of your glasses you'll see e.g. 52▢18-140: lens width, bridge width, then temple (arm) length — all in mm.
Measure your face width
Measure across your face from temple to temple; the frame's total width should be close to this.
Match the lens width
Lens (eye) width is the number that most affects fit — use the recommendation as your anchor.
Copy a pair that fits
The most reliable method is to read the numbers off frames you already like and match them.
Frames in a range of lens widths.
View on Amazon →Screen glasses — check the lens width in mm.
View on Amazon →Tiny screwdrivers and screws to adjust the fit.
View on Amazon →Frequently asked questions
What do the numbers on glasses mean?
They are lens width, bridge width and temple (arm) length in millimetres — for example 52-18-140.
How do I know my frame size?
Measure your face width temple to temple and match the lens width, or read the three numbers from a pair that already fits you.
How this is calculated
Frames are described by three millimetre figures: lens (eye) width, bridge width and temple length. We suggest a lens-width band from your face width (temple to temple): narrow faces suit ~48–50 mm lenses, average ~51–53 mm, wide ~54–56 mm. The surest method is to copy the numbers from frames that already fit.
Sources: Standard eyewear measurement system (lens-bridge-temple, mm), 2026.