Glasses Frame Size Guide

Medically reviewed by Sharon Copeland on 30 April 2021

Understanding the frame measurements of your glasses is essential as this will affect how the glasses sit on your face. If your glasses don't sit properly on your face, they may slide off frequently, resulting in them not aligning correctly with the centre of your eyes. This misalignment can cause blurry vision which can then lead to discomfort and headaches as well as having to strain your eyes more.

Glasses are made to fit a generalised measurement of most people’s faces. You will find that some styles of glasses come in a smaller sized frame for smaller or slimmer faces. Our handy guide will help you find the perfect frames with the best lenses to fit your face.

How are glasses measurements usually written?

The measurement of your prescription glasses is shown as three numbers which will usually look something like this:

54 - 18 -137

Where can I find the measurements of my glasses?

If you open your glasses up, you'll find the measurements of your glasses on the inside of one of the temple arms. This will be shown in three numbers as seen in the example below:

Please note you can have a leeway of 2-3mm on each measurement for the width and the temple arm length. For the bridge, you have a leeway of 2mm.

What do my glasses measurements mean?

The measurements of your glasses are the dimensions of the frame, typically written in millimetres. The first number shows the diameter of the lenses. The second number indicates the width of the bridge (across your nose) and the third number shows the length of the temple/arms. Here is a short guide on how to understand these numbers.

Top Tips for glasses measurements

These top tips for glasses measurements will ensure you get the best fit.

Frame Width

When measuring the frame width, make sure to measure from the furthest extended points of each side and include any frame parts/lugs which stick out on the sides of the frame.

Lens height

This measurement is especially important for progressive/varifocal or bifocal lenses. The minimum recommended lens height should be no less than 30mm.

Bridge width

If the glasses are too tight, they will squeeze your nose and feel uncomfortable. If your glasses are the correct bridge size, they will sit comfortably on the face.

Choosing a frame which has adjustable nose pads will allow you to conduct different adjustments/modifications, resulting in a more comfortable fit.

Temple arm length

This measurement is always the biggest number. The standard and most common length sizes are 135, 140 and 145mm.

You'll know if the temple size is right for you if the arms are long enough to sit comfortably over your ears.

1. Start by measuring from the hinge (metal joint which attaches the frame front to the temple) to the point where the temple begins to bend downwards.
2. Next, measure the length of the drop, which is from the top of the bend to the bottom end tip.
3. Adding both measurements will give you the total temple arm length.

Lens diameter/Lens width

The size of your lenses is mostly determined by the design of your frame as well as your prescription.

For high prescriptions, if the sphere (sph) is over +5.00 or -5.00, it is best to choose a frame which has a lens width below 50 mm.

If the measurements are not included on your glasses, fear not. You can measure the dimensions yourself with a millimetre ruler.

Out of all the measurements, the crucial one is the frame width. You won’t be able to find this written on the frame/temple arm. However, see our Glasses frame sizes below to help you choose the right size and measure the frame width.

Glasses frame sizes at Feel Good Contacts

At Feel Good Contacts, we stock three different frame sizes; small, medium and large. The measurements for our frames sizes are detailed below.