How to Measure Your Face for Glasses at Home

The easiest way to find your size is to measure a pair of glasses you already own and love, using the three little numbers printed on the inside of the arm, lens width, bridge width and temple length. If you haven't got a pair to copy, you can measure your face directly with a ruler and a mirror in about two minutes. Match those measurements to the dimensions listed on each frame and you'll get the fit right without leaving your kitchen table. Here's exactly how, plus the few fit checks that separate "looks about right" from "actually fits."

The quickest method: copy a pair you already love

If you own a pair of glasses or sunglasses that genuinely fit well — no pinching, no sliding, no leaving-marks-on-your-nose — you're already most of the way there. The whole spec is usually printed in tiny figures along the inside of one temple arm. Something like 52▢18-145 or 52-18-145.

The same three numbers, written two ways — with a square separator, or with dashes.

Those three numbers are, in order:

Lens width — the width of one lens at its widest, in millimetres (the 52). This is the single most important number for how a frame sits on your face.

Bridge width — the gap between the two lenses, where the frame rests on your nose (the 18). The little ▢ symbol or dash is just the separator.

Temple length — the length of the arm, from hinge to the tip that sits behind your ear (the 145).

Jot those three down, and you've got your reference size. When you're browsing, look for frames with similar numbers and you'll be in safe territory. (We list lens, bridge and temple measurements, plus the total frame width, on every product page for exactly this reason — no squinting at tiny engravings required.)

No pair to copy? Measure your face directly

If you're starting from scratch, you only need a ruler (preferably one with millimetres) and a mirror. Here are the two measurements that matter most.

1. Your face width. Stand about 20 cm from a mirror and hold the ruler horizontally across your face, level with your eyes, spanning from the side of one temple to the other (roughly where the arms of your glasses would sit). Read off the width in millimetres. Most adult faces land somewhere between about 130 and 150 mm. You want a frame whose total width is close to this. The golden rule: the front of the frame shouldn't extend much beyond the sides of your face, and it shouldn't dig in either.

2. Your eye-to-eye spacing (a rough guide). While you're there, you can eyeball roughly how far apart your eyes are, which gives you a feel for whether you suit a narrower or wider bridge. Closer-set eyes tend to prefer a slightly wider bridge; wider-set eyes, a narrower one. This is a gentle steer rather than a precise science; the face-width number above does most of the work.

That's it. Two numbers, two minutes, and you've got a target size to shop against.

What "good fit" actually looks like

Numbers get you close; these four checks confirm it. Whether you're measuring an old pair or trying a new one, a frame fits when:

The width matches your face. The frame front sits flush, not floating out past your temples like a tiny shelf, and not squeezing the sides of your head. If a new pair leaves dents at your temples or slides down constantly, the width is off.

Your eyes sit roughly centred in the lenses. Not crammed into the inner corners, not marooned out by the edges. Centred eyes are the quiet difference between glasses that look made-for-you and glasses that look borrowed.

The bridge rests without pinching or sliding. This is all down to that bridge number. Too tight and it pinches; too loose and the whole thing heads south every time you look down.

The arms reach your ears without pressing. Temple length should let the arm sit lightly over and behind the ear, holding the frame in place without leaving a sore spot by lunchtime.

If you'd rather skip the maths entirely, our Fit Finder quiz walks you through a few quick questions and points you toward frames in your size, and the Virtual Try-On button on any product page lets you see them on your own face before you commit.

A quick word on PD (pupillary distance)

If you're ordering prescription lenses, there's one more measurement: your PD, or pupillary distance, this is the gap between the centres of your two pupils, in millimetres. It matters because it lets the lab line up the optical centre of each lens with your eyes, so you're looking through the sharpest part. (For non-prescription sunglasses, you can happily ignore all of this.)

You can measure it at home: stand about 20 cm from a mirror, hold a ruler across your brow, line the zero up with the centre of one pupil and read off the millimetres at the centre of the other. Most adults land somewhere in the low-to-mid 60s. The honest truth, though, is that PD is fiddly to get right with a bathroom ruler, and a couple of millimetres out can leave a prescription lens feeling slightly off, so for this one, do yourself a favour and use our virtual PD tool: just tap Virtual Try-On on any product page and follow the steps in the app. It uses your camera to measure far more accurately than you (or, frankly, I) can manage freehand.

Putting it together

Find your three numbers, from a pair you love or from your own face, check the four fit points and let our PD tool handle the prescription bit. Once you know your size, choosing becomes the fun part rather than the gamble: you can shop for shape, colour and mood instead of crossing your fingers on whether it'll fit. If you're not sure which shapes suit you, our guide to choosing glasses for your face shape is the natural next read, and the women's and men's collections list every measurement you'll need.

Frequently asked questions

How do I measure my face for glasses at home? The easiest method is to read the three numbers printed inside the arm of a pair that already fits you: lens width, bridge width and temple length and then shop for similar dimensions. If you don't have a pair to copy, measure your face width in millimetres with a ruler held level across your eyes in a mirror, and choose a frame whose total width is close to that number.

What do the numbers on my glasses mean? They're three measurements in millimetres: lens width (the size of one lens), bridge width (the gap that rests on your nose), and temple length (the length of the arm). They usually appear inside the temple arm in the format 52▢18-145 or 52-18-145, separated by a small square symbol or dash.

How do I know what size glasses to buy? Match the frame's measurements to either a pair you already wear comfortably or to your measured face width. The most important figures are the total frame width (it should roughly match your face width without extending past it) and the bridge width (which controls how it sits on your nose).

What is the average face width for glasses? Most adult faces fall somewhere between roughly 130 and 150 mm across, but there's wide natural variation, so it's always best to measure your own. Your aim is a frame whose total width sits close to your face width: flush at the sides, neither pinching nor floating out beyond your temples.

How do I measure my pupillary distance (PD) at home? You can measure it with a ruler and mirror: line the zero up with the centre of one pupil and read the millimetre mark at the centre of the other, roughly 20 cm from the mirror. Because PD is easy to get slightly wrong by hand, we recommend using our virtual PD tool inside the Virtual Try-On app for an accurate reading. This only matters for prescription lenses.

What happens if my glasses are the wrong size? Too wide and they slide down or look oversized; too narrow and they pinch your temples and leave marks. The wrong bridge width makes them sit too high or too low, and the wrong temple length means they either won't stay put or press behind your ears. Getting the measurements right first time avoids all of it!