To get started, you'll need a mirror, a ruler with millimeter (mm) measurements – or even better, a flexible tape measure – and maybe a friend to help ensure accuracy. You’re going to use all of these to work out the necessary frame width, bridge width, and temple length of your glasses.

Frame width

The frame width is the total horizontal length of the glasses. To find this, measure the distance between your temples by looking in the mirror and placing your ruler or measuring directly over your face, above your brow. Record all the measurements in millimeters.

Bridge Width

The bridge width of glasses is the distance between one lens and the other.

To get the corresponding measurement at home, place the ruler on the bridge of your nose and measure its width.

The bridge width usually ranges from 15 to 25 mm.

Temple Length

Temple length refers to the arms of the glasses. Measure from the edge of your eyebrow all the way around your ear, to where you want the tip of the glasses temple to reach, as demonstrated in the image below.

Most temples have a bend to hook over the ears, so ensure the length you choose accommodates this curve for a snug fit.

And there you have it! The glasses you order don’t need to match up exactly to the measurements you’ve taken, but you can use the ranges provided in our guide to choose from S, M, L, or XL.