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Four young people in Palm Springs wearing Knockaround sunglasses

Measuring Your Head for Perfectly Fitting Sunglasses

March 11, 2022

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So, you've spotted the absolutely perfect pair of sunglasses; your mind is already running through your favorite outfits, positive that these new shades will go wonderfully with all of them. But when you try on those new sunglasses, something feels off. It might be something physical—pinching or slipping—but more often when this happens, it's something less identifiable. Until you realize that while the sunglasses are truly as awesome as you first believed, they just don't match your head size. So, let's look at how to measure yourself for perfectly fitting shades.


Get Your Ruler Ready

You're going to take some basic measurements of your head. A tailor tape works best, but if you don't have one of those, a standard ruler will work. Just make sure it's got millimeter markings to give you precise numbers. They'll be important when you want to match up the measurements of your head with those of sunglasses, which are usually listed in millimeters.

Temple To Temple Measurement

Using a mirror, position the ruler beneath your eyes and across your face horizontally to measure from temple to temple. The number you get will probably be somewhere in between 120mm and 150mm. While gender doesn't necessarily determine a person's length from temple to temple, it's common for men to measure around 145mm and for women to measure about 135mm. If you’re got a small to medium-size head, you might try out Mary Janes, Seventy Nines, or Classics. Larger heads match well with Mai Tais, Torrey Pines, and Fort Knocks.

Knowing the distance between a person's two temples is the main way to determine the best frame size according to lenses. If your measurement is on the lower end, say 120mm to 130mm, you're likely going to want to get sunglasses with lenses that are from 49mm to 54mm in width. Like a pair of Pacific Palisades. Those people in the middle, with temple-to-temple measurements running from 135mm to 140mm, would most likely pair well with lenses that run in width from 55mm to 57mm, such as Mile Highs or Deja Views. Folks on the wide side of the measurement range, 146mm to 152mm from temple to temple, probably pair best with sunglasses that have lens widths measuring from 58mm and higher, such as Torrey Pines.

Getting the Lens Size Right

The lenses of sunglasses traditionally run from about 40mm to 60mm. One good way of determining your perfect lens size is to compare the overall length of sunglasses to your temple-to-temple measurement. You can easily figure out the length of the sunglasses by adding the two lenses and the bridge. So, for example, a pair of sunglasses with 54mm lenses and a 20mm bridge would be 54 + 54 + 20 = 128mm—and these sunglasses would most likely be well-sized for a person with a temple-to-temple measurement from 126mm to 130mm.

There's also a handy trick that requires no math! Place a credit card vertically at the center of your nose. If the end of the credit card goes past your eye, you probably want smaller lenses. If the card doesn't reach your eye's end, then larger lenses are for you. If the card's end goes right to your eye's end, then look for lens sizes in the middle.

The Size and Position of Your Nasal Bridge

The measurement of the bridge of your nose should correlate with the bridge size of your sunglasses; this bridge size is the distance between the two lenses and an important aspect of finding the right fit. You can eyeball this one, determining if you have a wide or narrow bridge. As a rule of thumb, you likely have a wide bridge if your eyes are farther apart, and a narrow bridge if your eyes are closer together. Narrow noses usually fit well with sunglasses that have bridges in the 14mm to 18mm range, like Fast Lanes, while wider noses lend themselves to shades with bridge sizes that are 18mm and up, like our Paso Robles.

Take note of the position of your nasal bridge as well—a selfie of your side profile can be a big help here. You want to determine if your bridge is above or below your pupils. If it's above, you'll want to try out sunglasses that have bridges measuring between 19mm and 21mm. If the bridge of your nose is below your pupils, then glasses with bridges that span between 16mm and 18mm are probably for you.

Frame thickness is also good to consider in conjunction with the bridge measurements, as thicker frames lend themselves well to wider bridges that are made to hold up more weight. So, for example, you may see a pair of glasses you want that have thick frames, but you have a narrow nasal bridge that's above your pupils. In that case, instead of sunglasses with bridges between 16mm and 18mm, such as Mount Evans, you may go up to 19mm or 20mm. Or the reverse. You may have a high nose bridge that would traditionally fit well with glasses that have 20mm bridges. But if they're thin-frame glasses, you might try out some with 18mm bridges.

And after you figure out your head size, Knockaround is here with a wide variety of frame sizes and styles that are sure to pair perfectly with you. If you're still unsure which pair is right for you, take our short quiz to find out!

Written by William McCleary for Knockaround.

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