Eyeglass Frame Size Guide: How to Find Your Perfect Fit
Finding the right frame size is essential for comfortable, great-fitting glasses. Understanding eyewear measurements can help you choose frames that fit your face properly and feel comfortable for everyday wear.
Most glasses include three key measurements printed on the inside of the temple arm, such as: 49-21-140
- 49mm = Lens Width
- 21mm = Bridge Width
- 140mm = Temple Length
Table of Contents
Understanding Eyeglass Measurements
Eyeglass measurements help you understand how wide, tall, and long a frame is. Comparing these measurements with a comfortable pair you already own can make it easier to find your ideal fit.
Lens Width
Lens width is the horizontal measurement of each lens at its widest point. In a frame measurement such as "49-21-140," the number 49 represents a lens width of 49 millimeters.
A larger lens width creates a bigger, wider frame appearance, while a smaller lens width creates a smaller and more compact fit.
Bridge Width
Bridge width measures the distance between the two lenses across the nose. In the example "49-21-140," the number 21 represents a bridge width of 21 millimeters.
Choosing the correct bridge width helps ensure your glasses sit comfortably without feeling too tight or sliding down your nose.
If you have a low or narrow nose bridge, frames with adjustable nose pads (usually metal and titanium styles) tend to sit more securely than a fixed acetate bridge.
Temple Length
Temple length measures the arms of the glasses from the hinge to the end that rests behind your ears. In the measurement example "49-21-140," the number 140 represents the temple length in millimeters.
The correct temple length helps keep your glasses secure and comfortable throughout the day.
Lens Height
Lens height measures the vertical distance from the top to the bottom of each lens. Although it is not usually included in the standard frame measurement numbers, it is an important measurement for certain lens types.
A larger lens height can provide more vertical space, which can be especially helpful for:
- Progressive lenses
- Customers who prefer more lens coverage
Progressive-friendly frames: Most of our frames can be made with progressive lenses. Frames marked "Progressive-friendly" on the product page have a lens height of 28 mm or more, giving you a roomier reading area. Not sure about a frame? Contact us before ordering.
Frame Width
Frame width measures the total width of the glasses from one side to the other, including both lenses and the bridge.
This measurement helps determine whether a frame matches your overall face width. A properly sized frame should feel comfortable without squeezing your temples or feeling too loose.
How to Find Your Glasses Size
The easiest way to find your ideal frame size is to check a pair of glasses you already own that fits comfortably.
Look at the inside of the temple arm for a series of numbers, such as: 49-21-140
You can use these measurements as a reference when choosing your next pair of glasses. While exact measurements do not need to be identical, staying close to your current frame size is usually a good starting point.
No Glasses to Compare? Measure Your Face
- Stand in front of a mirror and hold a ruler (in millimeters) horizontally at eye level.
- Measure straight across from the edge of one temple to the other, just in front of where your ears start.
- Choose frames with a total width close to that number, within about 5 mm either way.
Tip: if you're between two fits, choose the wider one for comfort, or the narrower one if you prefer a snug, compact look.
Frame Fit: Narrow, Medium or Wide
Each product page shows a frame's fit based on its total frame width, the best single number for judging whether glasses will suit the width of your face. Compare it with the total width of a pair you already own and find comfortable.
| Fit | Total Frame Width | Best For |
|---|---|---|
| Narrow | Under 135mm | Narrower faces and petite fits |
| Medium | 135–142mm | Most face widths |
| Wide | 143mm and above | Wider faces and roomier fits |
How do these ranges compare across the industry?
Frames are measured the same way everywhere: lens width, bridge width and temple length (for example, 52-18-140) follow the international "boxing system" standard. There is no official standard for what counts as narrow, medium or wide, so each retailer sets its own ranges. Most online eyewear stores group frames by total width at roughly 130–135 mm and under for narrow, around 135–142 mm for medium, and about 140–143 mm and up for wide. Our ranges sit in line with these, but a frame listed as "Medium" elsewhere may fall a few millimeters differently here, so comparing the actual total width is always the most reliable check.
Fit is a guide, not a rule: bridge width, temple length and frame shape also affect comfort. Staying within a few millimeters of a pair that already fits you is usually a safe choice.
Signs a Frame Doesn't Fit
- Pinches at the temples or leaves marks: try a wider fit.
- Slides down your nose: look for a narrower bridge or adjustable nose pads.
- Your eyes sit near the outer edge of the lenses: the frame is too wide, so try a narrower fit.
- Arms press behind your ears or don't reach: check the temple length (most adults wear 140–145 mm).
For more detail, see How Should Glasses Fit? 9 Signs Your Eyeglasses Fit Correctly.
Find Your Perfect Fit
Ready to order? You'll also need your pupillary distance (PD). Here's how to measure your PD at home.
- Browse all eyeglasses. Every product page shows its fit and measurements.
- Try frames on with virtual try-on.
- Have a small face? See our small face fit guide.
Still unsure? Contact us with your current frame's numbers and we'll help you choose.