Finding Your Perfect Frame

Glasses Measurements & Frame Sizing Guide

Finding the right frame size is just as important as choosing the right style. Whether you’re buying your first pair or replacing a favourite frame, understanding how glasses measurements work will help you select the perfect fit quickly and confidently.

This guide covers everything you need to know to get started.

Why Glasses Measurements Matter for Comfort & Fit

Glasses that don't fit well can slip down your nose, pinch behind your ears, or sit awkwardly on your face. The right frame size ensures your glasses stay comfortably in place throughout the day, while also aligning your lenses correctly with your eyes for clear, balanced vision.

Proper measurements also help maintain the aesthetic you want, whether that's sleek and subtle or bold and oversized, without compromising on practicality.

Understanding Frame Measurements & Where to Find Them

Most glasses frames are measured in millimetres and follow a standard format: lens width, bridge width, and arm length.

For example, a frame labelled 52-18-140 means the lens is 52mm wide, the bridge (which sits over your nose) is 18mm wide, and the arms (or temples) are 140mm long. These three key numbers determine how your glasses will sit, feel and look, so it’s important to know what each one means when looking for a new glasses frame.

How Frame Measurements Affect Your Glasses

Frame measurements dictate how your glasses fit and can have a big impact on comfort and vision quality, it’s important to make sure you get the right fit.

Measurement	Where it is Measured	How it Affects Wear
Lens Width / Lens Diameter	This is measured across the lens from the bridge at its widest point.	Affects the overall size of the frame and how far apart the lenses sit. Larger lenses offer more coverage, while smaller ones provide a more compact look.
Bridge Width	This is the distance between your two lenses. Essentially, the length of the frame that sits directly above your nose.	Determines how the frame rests on your nose. A bridge that’s too wide can cause your glasses to slip, while one that’s too narrow may pinch or feel tight.
Arm Length / Temple Length	This is the length of the arm from the hinge to the tip, including the part that sits on your ear.	Affects how the glasses sit behind your ears and stay in place. If the arms are too short, they may press against your head. If too long, they might not stay secure.

There are also two other measurements that can be useful to know but aren't usually on the frame:

Frame Width	Measure the total width of the full-frame to give you an overall better picture of how these frames compare to your current glasses.	Determines how well your glasses fit your face overall. Too wide, and they may slip or look oversized; too narrow, and they can feel tight or leave marks. A proper fit ensures balance and comfort.
Lens Height / Depth	Measurement from the top to the bottom of the lens. All frames can be fitted with single-vision lenses. However, if you require a bifocal or varifocal lens, then this measurement becomes important, as these lenses will require a minimum lens height of 28mm.	Impacts both style and function. It’s important for varifocals and bifocals, and also shapes the overall look, taller lenses feel classic, while shorter ones offer a more modern touch.

Choosing Your New Frames

If you already own a pair of glasses that you are happy with, the process of choosing the right frame for you is very simple. By checking the frame sizes from your own pair against the sizes indicated on our site, you will be able to find a pair of glasses that fit comfortably, no matter their style!

We show the dimensions on all our frames (example below). Simply measure a frame you have at home and if your frame is within 5mm of the size of the frame on our site, you can safely say it will fit.

Find Your Frame Dimensions

Finding the Best Fit FAQs

How do I know my frame size?

Frame size can usually be found on the the arm of your glasses. However, if you cannot find the frame size of your glasses, simply follow our instruction vidio above to measure the size of your frames.

How do I choose glasses for my face shape?

Face shape plays a role in choosing frames that suit:

Round faces: Angular shapes like square or rectangular frames.
Oval faces: Most frame styles suit oval shapes, including round or square designs.
Square faces: Rounded or oval frames soften angular features.

Read our face shape guide for more detailed information on different face shapes.

What if my frame size isn’t available?

When your exact measurements aren’t available, choose a frame from us that’s within 5mm of your current pair. Adjustable nose pads or spring hinges can help fine-tune the fit.

What does “small,” “medium,” or “large” mean in frame sizes?

These refer to the total width of the frame:

Small: Less than 125mm
Medium: 126-130mm
Large: 131-135mm
Extra-large: More than 136mm

How do I ensure sunglasses fit properly?

For sunglasses, comfort is key. The frame size should be slightly larger than your regular glasses for better coverage.

What should I do if my glasses don’t fit right?

If the frames feel loose, too tight, or don’t align properly, adjustments can often be made at home or by a local optician. Most glasses can be adjusted at the bridge or temple tips for a more comfortable fit.

How do I adjust my glasses for a perfect fit at home?

You can make minor adjustments to your glasses for the following:

Temple arms: Gently bend the temple tips inward for a snugger fit or outward if they’re too tight.
Nose pads: Adjust with your fingers or a small tool to raise or lower the frames on your nose. Use minimal pressure at all times to prevent breaking the frames.