What Do the Numbers on Sunglasses Mean? (52-18-140 Explained)
Ever seen numbers like 52-18-140 on the arm of your sunglasses and wondered what they mean? They're the frame's measurements in millimeters — and knowing them is the easiest way to buy sunglasses that fit online. Here's the decoder.
The Three Sunglasses Numbers (mm)
| Number | What it is | Typical range |
|---|---|---|
| 1st (e.g. 52) | Lens width | 40–62 mm |
| 2nd (e.g. 18) | Bridge width | 14–24 mm |
| 3rd (e.g. 140) | Temple (arm) length | 120–150 mm |
Notes
First number — lens width. The width of one lens at its widest point, in millimeters (e.g. 52). It's the main driver of overall frame size: smaller numbers (40–50) suit narrower faces, larger (54–62) suit wider faces.
Second number — bridge width. The gap between the two lenses, where the frame rests on your nose (e.g. 18). A bridge that's too small pinches; too large slides down. It matters most for comfort and how high the glasses sit.
Third number — temple length. The length of the arm that goes over your ear (e.g. 140). Most adult frames are 135–145 mm; the arm should reach your ear comfortably without pressing.
How to find your size. The quickest way: read the numbers off a pair of sunglasses that already fit you well and buy a similar 52-18-140-style spec. If you're between frames, match the lens width and bridge first — those affect fit the most.
FAQs
What do the numbers on sunglasses mean?
They're three measurements in millimeters: lens width, bridge width, and temple (arm) length — for example 52-18-140 means a 52 mm lens, 18 mm bridge, and 140 mm temples. They tell you the frame's size and fit.
Which number matters most for fit?
Lens width and bridge width. Lens width sets the overall frame size for your face, and bridge width controls how the glasses rest on your nose. Temple length just needs to reach your ear comfortably.
How do I find my sunglasses size?
Read the numbers off a pair that already fits you well and match them. If you can't, measure your face width and start with a lens width around 50–54 mm for average faces, adjusting up or down.
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