Ever wondered what the writing on the inside arm of your sunglasses means? No, they’re not the combination to Al Capone’s safe — they’re measurements. Here’s what each of the numbers means — and how you can use them to help purchase your next pair of rad specs. This information can be incredibly useful particularly if you’re ordering online and can’t try on a pair before you purchase.
Look on the Inside Arm of Your Glasses
The easiest way to start is if you already have a pair you love and that fit perfectly. Just look on one of the inside arms for that pair’s measurements. If the numbers are too small to read, borrow your niece’s youthful eyeballs and have her tell you the three numbers on the inside. Or take a photo with your phone’s camera and enlarge the photo. Voilà! You’ll most likely see something like this:
The three numbers correspond to the lens/eye size, bridge size, and temple length, as shown in our Fit Information Guide:
Deciphering the Numbers
Measurements for glasses are given in millimeters, although many vintage glasses use inches. Here’s what each of the measurement trifecta means:
Lens/eye size: The entire width of the lens — but not the frame! Keep this in mind in case you’re considering switching from thick frames to thin frames, or vice versa.
Bridge: Also known as the DBL (distance between lenses).
Temple length: The entire length of the glasses’ arm.
Any other numbers on the arm could refer to the make or model number, or some other coding the manufacturer uses. If you don’t see any numbers, they may have worn off or it could just be that the manufacturer got lazy and chose not to include them.
Where possible, the Sunglass Museum provides measurements for each style of sunglasses in its shop to help you find just the right pair.
Look vs. Fit
You want to make sure you get the most use out of your purchase — if your specs don’t look or feel right, you’re much more likely to “accidentally” leave them on the beach or toss them out at the mall food court. A poor fit can lead to glasses that leave indentations in your nose, slide off your face, or even cause headaches if they’re too tight.
Although the measurement trifecta is important for fit, the shape of your face determines how your sunglasses will look. Both look and fit are incredibly important, but if you have to choose one over the other, you first have to determine the main purpose of your specs. If you’re wearing them on the red carpet, of course looks will take precedent. But if you’re going to be racing a car or driving a boat, you’ll want to make sure they sit squarely on your face and don’t move much. Safety first, people.