Glasses Measurements: How to Use Them While You Shop

Once upon time, if you needed a new pair of eyeglasses you’d go to an eyeglass showroom. You’d try on a million pairs (or realistically, more like five pairs since sometimes the selection was small), and then you’d pay A LOT of money to get the one pair of frames that looked really good on you.

But with the emergence of amazing online eyeglass shops, it’s become much easier to find cute eyeglass frames for less money. On the other hand, it’s less likely you’ll try on the glasses before you buy them. However, there’s a simple solution that’ll help you find flattering glasses online every time: Find your ideal glasses measurements.

Glasses measurements help you assess the fit of a pair of glasses so you can make sure the frame style you’re considering will look good with your face shape. We’ll explain what each eyeglass measurement means and show you how to use these numbers to find the right frames.

What Are the Different Glasses Measurements?

If you already own a pair of glasses, do this fun experiment with us. Look at the inside of the temples, or the arms, of the glasses (the part that goes behind your ear when you wear them). On one of the temples, you’ll notice a lot of information.

The info inscribed on the temple arm can include things like the brand name, model name, and model number of the glasses. You’ll also see three numbers written in the following format: XX-XX-XXX.

That’s not your eyewear’s date of birth — it’s the glasses measurements. If you own a pair of our Larkin frames, for example, you’ll see the numbers 51-17-140.

Those numbers are the lens width, the bridge width, and the temple arm length — in that order. And the measurements are always given in millimeters. So, in the example of our Larkin frames, the lens width is 51 mm, the bridge width is 17 mm, and the temple length is 140 mm.

These three numbers are the only glasses measurements that you’ll see imprinted on the inside of the frame, but there are two other measurements that you may come across when you shop for glasses online: the lens height and the frame width.

Understanding all five of these measurements will help you find the most stylish and comfortable eyeglass frames for your face. So, let’s break them down one by one.

Lens Width

This is the first number that appears in the measurements listed on the inside of your frames. It’s the horizontal width of the lens, and you can find it by measuring across the widest point of one of your lenses. The lens width should be just slightly wider than your eye size. If it’s too wide, it’ll make your eyes look like they’re too close to your nose. And if it’s too narrow, it’ll make your eyes look wide-set.

The lens width typically ranges from 40-60 mm.

Bridge Width

The second number listed on the inside of your frames, the bridge width is measured from where the frame meets your lens on one side of the bridge across the nose bridge to where it meets the lens on the other side.

If the bridge size is too narrow, the glasses will pinch your nose and feel uncomfortable when you wear them. If it’s too wide, the bridge of the glasses will rest across the top of your nose (instead of being supported by the nose pads), which will make the glasses feel heavy and possibly leave an indent on the bridge of your nose.

The bridge width typically ranges from 14-24 mm.

Temple Length

This is the last number listed on the inside of your frames. The length of the temple or the arms of the glasses is measured from where the side of the frame starts to curve back to where the arm ends. If the temple size is too short, it won’t comfortably reach past and rest over your ears. And if the temple size is too long, it’ll go too far past your ear, messing up your hairstyle and getting in the way of your hats.

The temple length typically ranges from 120-150 mm.

Lens Height

The lens height isn’t listed on the side of your glasses, but most online eyewear companies will include this measurement on their product pages. You can find the lens height for all Pair Eyewear frames under the “Fit Details” section. This measurement is taken from the top of the lens to the bottom at the lens’ longest point.

The lens height is important for two reasons. First, if you need specialty lenses, like progressive lenses or bifocals, your lenses will need to be a minimum height, typically 30 mm, in order to fit the multiple fields of vision into one lens. Secondly, if you have a small face or high cheekbones, you may want lenses with a shorter height so the bottom of your frames don’t rest on your cheeks and leave indentations.

The lens height typically ranges from 32-38 mm.

Frame Width

Also not listed on the inside of your glasses, but often included on the website, the frame width is the total width of your frames. To take this frame measurement, you would use a measuring tape across the widest part of your frames. Start on the left side of the frame, and measure from the outside edge of the frame, across the left lens, nose bridge, and right lens to the outer edge of the right side of the frame.

The frame width will determine how well the frames fit your face. If the width is too narrow, your face will look wide and the glasses may feel tight and be uncomfortable to wear. If the width is too wide, your face will look narrow and the glasses may feel loose and easily fall off when you look down or turn your head too quickly.

The frame width typically ranges from 125-138 mm.

How Do You Know Which Glasses Measurements Will Fit Your Face?

Now that you know what each of the measurements mean and how they’ll affect the look and feel of your glasses, let’s find the ideal measurement for you. If you have an old pair of glasses you love, start by checking the measurements on that pair. Use it as your reference point when you shop for new glasses.

If you don’t have an old pair, you’ll need to break out the measuring tape. For a good fit, your frame width should only be about one finger’s width wider than your face, and your eyes should be centered in the lenses.

You can find your ideal frame width by holding one finger on each side of your face, pressed up against the edge of your face. Grab your measuring tape and measure the distance from the outside of one finger to the inside of the next finger in millimeters. Glasses within 1-2 mm of that width should be a good frame size for your face.

But before you select your new glasses you should also consider bridge placement. Look at the bridge of your nose. Does it come up high on your face or is it lower down? If you have a low bridge, you’ll look good with glasses where the bridge comes lower and is closer to the center of the lenses. If you have a high bridge, you’ll look better and be more comfortable in glasses that have a high bridge set closer to the top of the lenses.

Finally, consider your face shape. The best glasses for heart-shaped faces and square faces are round, oval, or cat-eye glasses. The best glasses for round faces and oval faces are square and rectangular frames.

And if you’re still not sure which glasses will make you look like your most fabulous self, use our virtual try-on feature to find your best fit.

Shop Online With Confidence

Buying your glasses online can save you lots of money. (Pair Eyewear starts at just $60 a pair for single-vision lenses!) And with the right tools — from finding your ideal glasses measurements to using our virtual try-on tool — you can choose the perfect pair on your first try.

But, taking that leap and ordering prescription glasses you’ve never tried on before can be scary. At Pair Eyewear, we take the fear out of the process by offering free 30-day returns. So, go ahead — be adventurous! You can try on your new glasses at home and send them back if they’re not the perfect fit.

Once you fall in love with your pair, you’ll be ready to get even more adventurous by adding neon sparkles or comic book-themed Top Frames to mix up your style without buying a second pair of glasses. Pair Eyewear is always the perfect fit for your face and style.