Although buying glasses online is cheaper, an advantage of in-store service is that glasses can be tried on-location and even be professionally fitted.

However, not all of us can afford that luxury and you can save a lot of money by buying glasses online.

Since we’ve reviewed the best places to buy glasses online, we’ve created the following guide so you can find the right size and take your measurements.

Once you have learned everything that you need to know in this guide, you’ll be able to confidently buy glasses from the retailers we recommend linked above.

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How Should Glasses Fit Properly?

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One of the difficulties of buying glasses online is that it’s harder to get them properly fitted. Sometimes glasses may be too large or too small. Fortunately, the best online retailers offer generous return policies, which makes it easier.

However, to avoid making the same mistake twice, it’s important to learn how glasses should fit as well as learning the measurements. Many regular glasses wearers already know this but newcomers can find it confusing.

How Glasses Should Fit

Before we explore the technicalities of measuring glasses or even the best ones according to your head size, let’s talk about how glasses should fit. In short, this is the most basic and important element, which you need to know.

Once you’ve learned this, you could be fine without knowing the rest. However, we still recommend that you learn about measurements for when shopping online. Additionally, knowing the best frames for your head size could save you a lot of time in searching.

Generally, glasses fit according to the following parameters:

  1. Frame Width
  2. Arm Length
  3. Bridge Width

These will be the overarching topics that we’ll cover and you can click on them to jump straight to the subject that’s important to you.

Before you do so, you need to know that these core features break up to include other considerations. For instance, the frame width needs to also take into account the pupil placement. Meanwhile, the bridge width also affects how high it sits on the nose.

How Glasses Should Fit Properly

The above graphic is a handy reference, which you can use to tick off each of these factors. Now that you’re aware of this, either scroll down to read more or use the links in the list above to jump ahead.

1. Frame Width & Pupil Placement

As mentioned above, the width of the frames and pupil placement are inextricably linked, which is why we grouped them together.

Frame width (a.k.a. “total width”) should only barely extend past your cheekbones. If you can fit more than one finger between the arm and your temple, the frame is too wide. On the other hand, if the arm and your temple touch, the frame is too narrow.

Improper frame width will inevitably affect the placement of your pupils within each lens. Below we see examples of pupils too far toward the outside of the lens as well as too close to the inside.

Glasses With Front Too Narrow

Glasses With Front Too Wide

Vertically speaking, imagine your lens split into three horizontal sections. your pupil should land just about where the middle and upper thirds meet. That last bit is particularly important for those who wear progressive lenses or bifocals, as this allows more room for the different portions of the lens.

2. Arm Length

Glasses With Sides Too Short

Glasses’ arms (also known as “temples”) should extend straight back to your ears and only touch the side of your head just in front of your ears. The arms must also not curve too early; if they do, this will push the glasses down on your nose.

Not only does it make the glasses seem unusual due to an incorrect fit but it’s also uncomfortable. Extra pressure will be applied to the bridge, which can cause headaches and sinus problems.

Furthermore, your prescription will have been designed for the lenses to sit correctly on the nose. With the temple arms being too short, they may be pushed too close to your face.

3. Bridge Width & Height

Glasses With Bridge Too HighThe bridge (the part that goes over your nose) should fit snugly, neither too tight nor too loose. Metal glasses often have adjustable nose pads to aid in achieving a proper fit, but acetate ones often don’t.

Keep this in mind if you’re measuring yourself, as you’ll have to be more exacting if you prefer plastic/acetate frames.

A too-tight bridge will be uncomfortable and compromise your vision correction by keeping the glasses too high on the face. A too-loose bridge will allow the glasses to fall down on your nose, requiring constant readjustment.

How To Measure Glasses Size

First things first: if you already wear glasses, there are likely some measurements already indicated on the left temple, or perhaps on the inside of the bridge. It’s probably a sequence of two two-digit numbers or two two-digit numbers followed by a three-digit number. This is referred to as a “string.” If you already own glasses that fit well, just use these measurements when placing orders online.

Below, we see an example:

Glasses measurements on clubmasters

Let’s assume that the string says 50-21-140. This corresponds to the following, in millimeters:

Lens Width – Bridge Width – Temple Length

Note that two-number strings refer to lens and bridge width only.

Lens width varies widely due to the plethora of styles and sizes of lenses available. Bridge widths generally average between 16-23mm. Temple length is typically offered in 135, 140, 145, and 150mm measurements.

Taking Your Own Glasses Measurements

For the left-brained amongst us, you might enjoy knowing exactly what these measurements are and how you can get them. Thankfully, getting these measurements is pretty quick and easy, and all but one of them can be done by yourself! Below, we outline all of the key glasses measurements:

If there’s one in particular that you’re looking to measure, simply click on it above to jump straight there. Note that all measurements are in millimeters. All you have to do is follow the purple arrow in the illustrations below with measuring tape!

How To Measure The Frame Width

what is glasses frame width

Also referred to as “total width,” this is arguably the most important measurement of all. As we touched on above, if the frames are too narrow, your head will look too big. Conversely, if the frames are too wide, your head will look puny by comparison.

Simply measure across the widest part of the frame, including any bits that stick out on either end.

How To Measure The Bridge Width

how to measure bridge width for glasses

The bridge connects the lenses and rests on the bridge of your nose, hence its name. It’s also important to get this measurement as accurate as possible for long-term comfort.

Measure across the frames’ bridge where they rest on your nose’s bridge.

How To Measure The Temple Length

graphic of glasses temple length

Glasses’ temples are also referred to as their “arms.” These need to be long enough to extend far back enough to fit comfortably on your ears. If they’re too short, that will push the bridge down too far on your nose, resulting in an improper, uncomfortable fit.

Measuring here is a two-step process: measure the arm to its “elbow,” then measure from the elbow down to the end closest to your neck.

How To Measure The Pupillary Distance

graphic showing pupillary distance on face

This is the distance between your pupils and is used to determine where they fall inside each lens. You will need a friend to take this measurement as it’s difficult to get an accurate one by yourself. Remember that your pupils should be centered in the lens from left to right and straddle the upper two-thirds of the lens from top to bottom.

Take a measuring tape and have a friend measure the distance from the center of one pupil to the other.

How To Measure The Lens Height

where to measure glasses lens height

A less crucial measurement than the others (you have a bit more leeway here), this is simply the height of the lens at its tallest point.

Measure the lenses from top to bottom at their highest point.

How To Measure The Lens Width

how to measure glasses lens width

Similar to lens height, just in the other direction. Simply measure the width of the lens at its widest point.

Measure the lenses from left to right at their widest point.

The Best Glasses According To Head Size

Firstly, be aware that any head size can usually wear any frame style as a general rule. As long as the frame properly fits you as outlined above, there should be no problems.

This is good to know as it means you can let your needs and personal tastes dictate how you choose your glasses. Fortunately, your body measurements won’t be an obstacle that you can’t overcome.

Small, medium, and large heads

With that said, a good rule of thumb is that smaller heads take to smaller frames better, while larger heads sync better with larger frames. Even with this in mind, there will be overlap.

The whole idea is to achieve a sense of balance: don’t overwhelm small heads with large frame styles, and don’t make big heads look bigger by sticking tiny frames on them.

This school of thought edges towards our use of face shapes when choosing glasses. We cover this in every one of our frame guides so you’ll know whether the style may work for you or not.

We’ve made this section very simple to follow and head sizes are broken down into 3 categories:

You can jump straight to your head size by clicking on it above if you already know it. Note that head size often corresponds to your overall frame. If you need help determining what your frame is, see our guide to body types.

Best Glasses For Small Heads

side view of man wearing glassesIf you have a smaller body frame, the chances are that you also have a smaller head. Therefore, we would tend to recommend smaller, more delicate frames to complement this. However, as long as the measurements are correct and they fit, there will be less of a chance that your face is overrun by large frames.

Ideal Frames For Small Heads

Best Glasses For Medium Heads

man in clear glasses frames

If you are of an average build, you’ll likely have the freedom to wear pretty much any frame. Just remember that your face shape will also play a role in this. Therefore, consider identifying your face shape, which will lead you to consulting the best options.

Ideal Frames For Medium Heads

Best Glasses For Large Heads

bald man in flat top glassesIf you’re a generally larger gentleman, you probably have a relatively larger head too. Consider opting for frames from the opposite perspective of a small man. This means aiming for frames with larger proportions.

If they’re too small, they may make your face look even larger in comparison. Just remember that as long as they properly fit, you should be fine.

Ideal Frames For Large Heads

Now What?

A pair of properly fitting glasses can mean the difference between comfortable vision correction and uncomfortable eyewear. Correct fit is also important for aesthetic reasons: well-fitted glasses will add to your visage without taking anything away, whereas ill-fitting glasses will serve as a distraction to anyone looking at you.

Now that you have read about how to properly size your glasses, consider also some of the following guides:

Glasses Fitting Guide
Reviewed by Patrick J, on .
"Using this guide really helped me. My glasses look and feel great when I wear them now."
Rating: 5.0 ★★★★★

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