A Guide to Glasses Measurements

At our Kerrisdale optical store, we’re experts at getting our customers into the perfect fitting pair of eyeglasses. Not only are we familiar with what looks good on you based on factors like face shape, we also take measurements to ensure frames are comfortable, sit properly on your face and most importantly, help you see clearly. While it may seem really easy to go online, click on a pretty pair of cheap frames and order glasses, there’s actually much more to it and there’s no substitute for visiting a store in person and being measured. Plus, frames don’t come in a set size like shoes. The size of a frame is more of an indication that they may work for you and not a guarantee, which is why DIY measurements can be perilous. While we take certain measurements, which we’ll go over, you’ll also need to try on frames to get the fit you want.

Nose Bridge Measurement

We did a detailed post on getting the bridge fit right, which you may want to read to get the entire scoop. But basically, bridge width is the distance between lenses when measured from inside the rim across the frame. Eyeglass frames have three numbers and will read something like 55-16-140. The middle number is the bridge width and it ranges from 14 to 24. A narrower bridge will measure somewhere between 14mm to 18mm while an average or wider bridge will be 18mm or higher. But just because you wore a pair with a bridge width of 18mm before, doesn’t mean that will work every time. Since plastic frames come in a variety of styles, they aren’t all constructed the same way and this can affect the fit.

Box Measurement

The first number in that string of three numbers on eyeglass frames is the box measurement, which is the effective diameter of the lens, so the widest distance of the overall frame.

Temple Length

The “stems” on either side of the frames that rest over your ears and connect to the front are known as temple arms. The third number in the aforementioned 55-15-140 example refers to the temple length. The most common measurements for temple length are 135mm, 140mm, 145mm or 150mm. The temple arms should be long enough that they sit securely yet comfortably on top of the ear without pinching.

While all of these measurements come into play when narrowing down your glasses options, the most relevant piece of information is actually the overall measurement of the frame which is calculated with the following equation: (Effective Diameter x 2) + (Bridge) = Overall Size. Yet, keep in mind, as we said before, this isn’t exact and the bridge size can make a big difference in where the lenses fit as far as the centering of your eyes. Fashion has a big impact on how we see fit too, as does modification. At The Spectacle Shoppe in Kerrisdale, we can help you determine these measurements and fit you for frames that look and feel amazing. We can also modify certain frames to fit even if they don’t work “off the board.” Stop by today to find your next pair of glasses.

Morgan Nahanee
Morgan Nahanee


Morgan is The Spectacle Shoppe’s Lead Technician and Customer Relations Specialist as well as a Principle of Spectacle Shoppe. She is a licensed contact lens fitter and dispensing optician and has been working for The Spectacle Shoppe since 2006. She graduated from Douglas College’s two year Dispensing Optician and Contact Lens Fitting Program in 2008. From contact lens fitting to eyeglass repairs and adjustments Morgan is eager to help you with any optical needs. Connect with Morgan Nahanee on Google+