# How are glasses sized

**URL:** <https://boards.straightdope.com/t/how-are-glasses-sized/156651>\
**Category:** Factual Questions\
**Created:** [February 21, 2003, 10:35pm UTC](https://boards.straightdope.com/t/how-are-glasses-sized/156651 "2003-02-21T22:35:00Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Tapioca\_Dextrin](https://avatars.discourse-cdn.com/v4/letter/t/3d9bf3/32.png) [@Tapioca\_Dextrin](https://boards.straightdope.com/u/Tapioca_Dextrin)\
**Post date:** [February 21, 2003, 10:35pm UTC](https://boards.straightdope.com/t/how-are-glasses-sized/156651/1 "2003-02-21T22:35:00Z")

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I’m in the market for a new pair of glasses. I’ve seen a couple of realy neat frames online. They appear to have some sort of size code like 32-42-138, in addition to the frame number. Does anyone know what these numbers refer to, or is it just a set of random numbers?

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**Author:** ![Belrix](https://avatars.discourse-cdn.com/v4/letter/b/ed655f/32.png) [@Belrix](https://boards.straightdope.com/u/Belrix)\
**Post date:** [February 21, 2003, 10:44pm UTC](https://boards.straightdope.com/t/how-are-glasses-sized/156651/2 "2003-02-21T22:44:02Z")

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Right on the inside of the nose bridge, at least in my last couple of pair, is a number with a square beside it. Mine currently have “54 ”. This is the size AFAIK.

Since many off-the-shelf glasses are made for smaller people, I’ve learned to look for this when shopping. If I like the frame but they seem small on my face, I’ve learned to ask if there’s a larger size available.

The store should have a book in which they can look-up the style and compare the number on the bridge to the list in the book and let you know if there’s a different size available.

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**Author:** ![mercaptan](https://avatars.discourse-cdn.com/v4/letter/m/898d66/32.png) [@mercaptan](https://boards.straightdope.com/u/mercaptan)\
**Post date:** [February 21, 2003, 11:34pm UTC](https://boards.straightdope.com/t/how-are-glasses-sized/156651/3 "2003-02-21T23:34:33Z")

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Usually two numbers. Mine are 5219. This is a size in millimeters. First is the width of the lens, second is the depth. The depth can be crucial if you wear bifocals/trifocals - ask your optitian. I imagine the third number might be the entire frame dimension horizontally?

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**Author:** ![Nametag](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nametag/32/406_2.png) [@Nametag](https://boards.straightdope.com/u/Nametag)\
**Post date:** [February 21, 2003, 11:54pm UTC](https://boards.straightdope.com/t/how-are-glasses-sized/156651/4 "2003-02-21T23:54:08Z")

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Depth? What the hell is frame depth? The second number is the distance between the lenses in millimeters. The third number is temple arm length.

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**Author:** ![wedgerat](https://avatars.discourse-cdn.com/v4/letter/w/e19b73/32.png) [@wedgerat](https://boards.straightdope.com/u/wedgerat)\
**Post date:** [February 22, 2003, 1:43am UTC](https://boards.straightdope.com/t/how-are-glasses-sized/156651/5 "2003-02-22T01:43:16Z")

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Maybe frame depth is the width of lens it can accomodate…

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**Author:** ![Captain\_Lance\_Murdoch](https://avatars.discourse-cdn.com/v4/letter/c/47e85d/32.png) [@Captain\_Lance\_Murdoch](https://boards.straightdope.com/u/Captain_Lance_Murdoch)\
**Post date:** [February 22, 2003, 2:00am UTC](https://boards.straightdope.com/t/how-are-glasses-sized/156651/6 "2003-02-22T02:00:47Z")

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The last number (the big one) is the length of the temples.