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find the right glasses size

Glasses Sizes — How to Find Your Number (+ Ray-Ban Chart)

by Eye-Shop. on 10-07-2026
Short answer: The glasses "number" is the lens width in mm — the first of the three numbers inside the temple (e.g. 52 □ 18 − 140). Rule of thumb: up to 49 = small, 50-54 = medium, 55+ = large. No old glasses to check? Do the card test below — it takes 10 seconds.

Updated: 10 July 2026 · By the Eye-Shop optician team

Size is the most common question when buying glasses online — and the easiest to answer correctly. With one of the 3 methods below you will know your number in under a minute, and with the Ray-Ban chart you will know exactly what to order.

Method 1: The glasses you already wear (the most reliable)

Take the glasses that fit you comfortably and look inside the temple: you will see three numbers, e.g. 52 □ 18 − 140 (lens width □ bridge − temple, all in millimetres). The first number is your guide: look for models within ±2mm of it.

⚠ The number doesn't tell you everything — the material matters too: the stated dimension measures only the lens opening, not the thickness of the rim. A metal frame in size 55 is overall much narrower than an acetate 55: the thick acetate rim adds to the total width four times over (two walls at each lens). In practice: a metal Aviator 55 is overall much smaller than a chunky-acetate Wayfarer 55 — same number, a completely different frame. When you move from metal to acetate, think 1-2mm smaller — and vice versa.

Method 2: The card test (no old glasses needed)

Every credit/debit card has a fixed width of 8.56 cm — about a medium lens + bridge. In front of a mirror:
  • Rest one edge of the card vertically against the centre of your nose.
  • See where the other edge reaches relative to the outer corner of your eye:
The edge of the card…Your sizeLens width
Goes past the corner of the eyeSmallup to 49mm
Reaches roughly the corner of the eyeMedium50-54mm
Does not reach the corner of the eyeLarge55mm+
The card test for glasses size - small, medium, large

Method 3: Measure your face

With a ruler or tape measure, measure the width of your face from temple to temple: up to ~12.5cm → small, 12.5-14cm → medium, over 14cm → large. Ideally the total frame width equals the width of your face — neither pinching at the temples nor "overhanging".

Size chart by brand — live

Choose a brand to see the models and the lens widths available right now in our stock — the chart updates automatically:
Ray-Ban modelLens widthStock
4940 WAYFARER PUFFER47–50mm18 in stock
3548N48–54mm11 in stock
3016 CLUBMASTER49–55mm11 in stock
2140 WAYFARER50–54mm11 in stock
3447 ROUND METAL50–53mm29 in stock
2132 New Wayfarer52–55mm13 in stock
2234 BRUNEL53–56mm14 in stock
3025 Aviator55–62mm44 in stock
3779 EXPLORER 356–59mm10 in stock
222457–60mm10 in stock
375559–62mm10 in stock
379159–62mm15 in stock
The data comes live from Eye-Shop stock and changes in real time. Fit tips: the Aviator wears "large" (a 55 = for small faces), the Clubmaster 49 suits small/medium, and the classic Wayfarer 2140 in 50 is the safe unisex size. See all Ray-Ban and the other sunglasses brands. Note: sports shields with a single lens (e.g. Oakley Sutro, Radar) are not included in the chart — their dimensions are measured differently and are not comparable with classic glasses.

The three dimension numbers on glasses
The three numbers are always printed on the inside of the temple
Choosing the right glasses size
Every product at Eye-Shop states its full dimensions — see the collection

At Eye-Shop you don't have to guess

  • Every product page states the full dimensions: lens width, bridge, temples, lens height and total width.
  • In the listings you can filter by number — see e.g. the Ray-Ban range and pick your size from the filters.
  • Torn between two numbers? Send us the model you wear now — we'll tell you exactly what fits you.

Size + shape = the perfect match

The number solves the fit; the shape solves the look. Once you have found your size, combine it with our guide on which glasses suit your face shape — or, for prescription, the right frame for your face shape.

Frequently Asked Questions: Glasses Sizes

How do I find out what size glasses I wear?
Look inside the temple of the glasses you already wear comfortably: three numbers, e.g. 52 18 140 — the first (lens width) is your "number". No old glasses? Do the card test (see above).
How do you do the card test for glasses size?
In front of a mirror, rest the edge of a card vertically against the centre of your nose: if the other edge goes past the outer corner of the eye → small; if it reaches level → medium; if it doesn't reach → large.
What do the three numbers on glasses mean, e.g. 52-18-140?
Lens width 52mm □ bridge 18mm − temple 140mm. All measured in millimetres and printed on the inside of the temple.
Does the same number fit me across all models?
Not necessarily — an Aviator 55 wears "larger" than a Wayfarer 54, because shape and bridge count too. That's why the size chart per model (above) is more useful than the number alone.
Does size matter for prescription and powered glasses?
Yes, doubly: on powered glasses the optical centre must line up with the pupil — a frame that is too large/small makes centring harder. See also our prescription frames.

TOPICS

Related categories: Sunglasses · Ray-Ban · Prescription glasses