If you have one, take a look along the inside of your glasses. You may find a series of numbers. These are the dimensions of your glasses frames. In addition to your eye prescription, eyeglass size is critical in helping you see clearly and comfortably.

In this guide, we’ve covered everything you need to know about eyewear measurements and finding the right frame size.

What do the measurement numbers on glasses mean?

The measurements on the frame will tell you the lens width, bridge width and temple length of your glasses. These three numbers are usually separated by spaces or dashes. Occasionally, you’ll find a small square between the first two numbers.

Lens Width

This will always be the first number in the sequence. Lens width is a measurement of the lens, sometimes called “eye size.” Lens width does not include the frame that holds the lens.

Lens width is usually between 40 mm and 60 mm.

Bridge Width

The width of the bridge measures the shortest distance between two lenses. Typically, this is at the top inner corner of the lens, right on the bridge portion of your frame.

Bridge width is between 14 mm and 24 mm.

Temple Length

Temple Length Measuring Temple Arm – It’s Easy! This starts with the screws that attach the temple arms to the rest of the frame and extends to the tips behind the ears.

Temple length is between 120 mm and 150 mm. It most commonly ends in a “0” or “5”.

Other Numbers

Depending on the manufacturer, you may also see some other numbers on the inside of the glasses. These reflect the style or model of the frame.

Two other important measurements are not printed on the temples: frame width and lens height. To determine these numbers, you’ll need to take your own measurements.


How do you calculate glasses size at home?

If your current glasses don’t fit well, or you’re shopping for your first pair, you may not have a current set of frames to refer to.

Don’t worry! Try these other ideas to help you find the perfect match for your new frame set.

Use a credit card to find your frame width

Most credit cards are the same size, 54mm on the short side. Place the credit card in the middle of the nose, with the short side just below the eyes.

If the card:

  • Extends past the corner of your eye, narrower frames are right for you.
  • Ends near the corner of your eye, medium frames are your best choice.
  • Ends before the corner of your eye, wide frames are the option for you.

Know the size of your nose

When you look in the mirror, notice whether your nose is narrow or wide. This can help you choose the correct frame size. Narrow noses are suitable for narrow nose bridges with spectacle frames. And a wide nose naturally suits a wider bridge of the nose.

Use a face shape finder

Knowing your face shape will help you find the best fit for you. For example, round or oval frames work best on people with square faces, while oversized lenses tend to look best on pear-shaped faces.