If you’ve ever shopped for eyeglasses or sunglasses, you’ve probably seen a string of numbers printed on the inside of the temple arm — something like 54-18-145. While these numbers might look confusing, they’re actually very simple and extremely useful when it comes to finding frames that fit comfortably and look great.
Let’s break down exactly what each of these numbers means.
54 — Lens Width (Eye Size)
The first number (in this case, 54) refers to the width of each lens, measured in millimeters. It typically ranges from about 40mm for small frames up to 60mm or more for oversized styles.
A 54mm lens width is considered medium-to-large, suitable for average or slightly wider faces.
18 — Bridge Width
The second number (18) is the bridge size — that’s the distance between the two lenses, measured at the part of the frame that rests on your nose. A bridge that’s too narrow will pinch, while one too wide may slip down.
An 18mm bridge is fairly standard and works for many people with an average nose bridge.
145 — Temple Length
The third number (145) is the temple length, which refers to the length of the “arms” or “temples” of the glasses, from the hinges all the way behind your ear.
Standard temple lengths usually run from 135mm to 150mm. A 145mm temple provides a comfortable fit for most adults, helping keep the frames in place without being too tight.
Why Frame Measurements Matter
Understanding these measurements helps you choose glasses that:
✅ fit comfortably
✅ sit properly on your nose
✅ look proportionate to your face
If you’re buying eyewear online, these numbers are essential to get the right fit. Even when trying frames in-store, knowing your preferred measurements can save you time and frustration.
A Quick Recap
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54 = lens width (each lens)
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18 = bridge width (between lenses)
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145 = temple length (arm length)
Next time you see these numbers, you’ll know exactly what they mean — and you’ll be better prepared to pick the perfect pair of glasses.
