What Do the Numbers On Your Glasses Mean?

You know – the tiny numbers on the inside of one of the arms of your glasses. They are usually near the temple of your head. Some are located close to your ear. What do they mean?

They’re eye frame measurements!

On your basic pair of glasses, you will find three numbers, which are basically size measurements of the glasses. There is usually a small square symbol between these first two numbers. Here is how to read the number on the glasses arm.

Every face is unique in its size and shape. Having the right measurements will go a long way to get a pair of glasses that suits you and fits properly. Many people focus only on the prescription. While that is obviously essential, the fit of the glasses on your face is also very important.

The First Number

This number is the width of each lens at the widest point. If you for example, see the number “48”, this tells you that the width of each lens is “48” millimeters wide. This number will range between 40mm to 60mm.

For bifocals and progressive lenses, manufacturers will often provide a separate measurements for the width and height.

The Middle Number

The Middle Number is the distance between the lenses and is sometimes referred to as the nose bridge size. (distance between each lens from the innermost measurement of each lens or the part of glasses that goes across the nose and connects the two lenses). If you see at “17” for example, then the distance between the two lenses is “15 millimeters. This width ranges from 14mm to 24mm.

The Third Number

The third number is the complete length of the arm of the glasses from the hinge to the where it ends near your ear. This is obviously the largest number. A common measurement would be “135” which means the length of the arm is “135” millimeters. The arm length is between 120mm to 150mm.

Other Numbers

The above three numbers are the typical measurement numbers. If you see additional numbers, they might be manufacturer model numbers. You can ignore these unless you wish to order the same pair. If there is an additional number like a +2.00, that indicates the strength of each lens in diopters and is generally reserved for reading glasses.

How to Use the Numbers

Armed with the three numbers and an understanding of what they mean, you will know everything you need to know to easily order prescription eyeglasses online. You will more likely receive glasses that properly fit your face and look stunning. Back in the day, we would just get an eye exam and be guided by sales associates on which glasses would be appropriate for our face shape.

In the event that you can’t find the numbers because they simply aren’t there, just take your own measurements with a ruler that has millimeter markings. Ask an optician to take the measurements if you don’t have a ruler with millimeter markings.

I decided to try this to look for a decent pair of reading glasses. It was so easy when I realized what those little numbers represent!

The deals out there are amazing really. You might want to try Zenni Optical, EyeBuyDirect, Clearly Glasses, Warby Parker, LensDirect or most retail stores that sell glasses.

There were a few things I really enjoyed about the experience of buying online:

1. The selection is huge;
2. Prices are competitive. If you find a sale, you will have hit the jackpot;
3. You can take all the time you need to decide;
4. Most websites allow you to visualize exactly what the glasses will look like on your face. So get creative and see your face as others see you;
5. Most online places will let you return unwanted frames without any hassle.

Here are some of the risks with buying online:

1. There are other fittings that are important and there are no measurements for these online: how glasses sit on your nose (high or low), curvature of the frame, and style of frame (round shapes have narrower lenses). 
2. Compare two different frames with the same measurements and one might fit you and the other might not. Similarly two different sizes in different models could both fit well.

So what are you waiting for?! Start searching for an exquisite pair of glasses that is perfectly suited to your face!