Should you use numbered or lettered sizing?

Keeping in mind that sizing is relative and that you can only afford to produce a limited number of sizes, how do you decide whether to use numbered (2-16)  or lettered (XS-XL) sizes? The cognitive shortcut (pt.2) is to do what brands you aspire to hang with do because you don’t have enough information (pt.2) to make a decision if you’re just starting out. If you think the sizing typical of your market could stand re-working or you just want to do your own thing, you can break the mold if your resources permit the risk. If this describes you, here is some guidance to figuring out which size scale to use.

The difference between the two scales is fit specificity, sales potential, cost savings and price points per size. Here’s a comparison of the two sizing strategies:

Lettered Sizes (XS-XL):

  • Fit silhouette is casual and not tightly fitted to the body.
  • Sales potential is greater per size since the sizing scale is more generous.
  • Cost savings are greater since you’re producing fewer sizes total.
  • Prices of lettered sized goods are typically lower than comparative goods with numbered sizes.

Numbered Sizes (2-16 etc):

  • Fit is more tightly defined, perhaps even tailored.
  • Sales potential per size is less as compared to lettered sizing. If we pretend you’re guaranteed to sell 100 size 2’s and 100 size 4’s, if you offered lettered sizing, you’d sell 200 XS’s.
  • Costs are increased as additional size cost more with respect to grading, labels, hang tags and all that.
  • Prices are usually higher, numbered sizes are more typically sold at higher price points.

Even so, there are variations depending on circumstances. Here is a such example of how this played out:

A designer wanted to maximize her sales potential by fitting a wider spectrum of customers so she wanted to use XS-L. However, since her niche is clothing for fit, petite women like herself (gymnast/ballerina figures), the fitting profile she envisions is quite specific and runs towards the smaller end of the size spread. Consequently, she thought to design her sizes like so:

XS (0-2)
S (2-4)
M (4-6)
L (8-10)

I said this wouldn’t do because it would be confusing to consumers. While sizes are relative and can vary quite a bit, they must approach a semblance of the norm. Specifically, her size 8-10 customer would never think to select the size Large even though her size scale works like this. Her size Large would still be a size or two smaller than most other lines’ size Medium. In this case I thought it would be better to use numbered sizes. Since the designer can only afford to develop five sizes at the outset, a bit of negotiation was in order to arrive at her final size spread -which was 2, 4, 6, 8, 10.  [It would not be appropriate to criticize this decision. She won’t be able to wear her own clothes (at the outset) because she would take a 0 but she’s not cutting that size.]

With respect to lettered sizes, keep in mind that these typically encompass two or more sizes. One might describe a size Small as size 2-4 but in reality, it’s a size 4 because it can’t be both. In fact, if one were combining sizes, it would be more honest to say one sold sizes 0, 4, 8, 12 and 16 but that would be very puzzling to shoppers.

The other thing about lettered sizes XS-XL is that there is an increasing expectation that these sizes are more aligned to the weight and size spread of the general population than to a given product line specifically. By that I mean, if you usually wear a Medium, you’ll most often expect to buy a Medium regardless of the brand you buy. The same couldn’t be said about numbered sizes because it is common for a size Medium buyer to wear anything from a 6 to a 12 depending on fabrication, silhouette and all that. Meaning, you’re less likely to get crosswise with consumers if you use numbered sizing for your stuff. The designer in this example would have had a lot of problems if she’d used lettered sizing because the customers who fit the profile of her size Large would typically buy a Small or maybe a Medium in most other brands.

A gentle reminder: Not everyone can afford to launch their line using numbered sizes since it can cost so much more to offer a full size range that will match consumer expectations.

And yes, this deals specifically with adult women’s sizing but it applies equally to men’s and children’s wear.

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  1. Liz says:

    Pardon the possibly dumb question, but could she sell combined number sizes, so the tag would read “0-2”, “4-6”, etc?

    She’s be limiting the number of sizes she makes, but not run into the “my L is your S” problem.

  2. Esther says:

    While it is possible to use lettered sizes in children’s wear, I don’t usually recommend it. I did develop lettered sizes for one customer but it was quickly abandoned because of the complexity. The size ranges are just too large. Usually DE’s don’t design just infant or toddler. They design 0-3M all the way up to 6X, for example. Integrating S-M-L without confusing both the retail buyer and the end consumer is very difficult.

  3. Susan says:

    Esther – do you have any thoughts re infant/toddler of sizing by range vs points. E.g. what are the cost benefits of saying size is 3-6m, vs saying 3m, or 6m? As a consumer I found the range easier to understand than the point sizing – but what your thoughts are.

  4. bente says:

    Sizing is confusing. For someone moving from one continent to another even more!
    I know several brands using both lettered sizes and number sizes. T-shirts or looser knits in letter sizes while the rest of the collection uses number sizes.

  5. Becky says:

    For specialty items, maybe it’s best to stay away from the usual numbers or letters and go with height or bust measurement or non-standard letters (like Chico’s does.)

    Competition swimsuits are sized by bust from 22 up to 42 – often with a Long option as well! And I like how H&M and Hanna Andersen’s children’s clothes are sized by height and/or age, plus an added “X size” which is for chunkier kids. (it is so much easier to ask how tall a kid is than their waist size!)

  6. Renee says:

    I am dealing with this right now for my pull-up cloth diapers. I have added sizes onto the size range three times in the 3+ years they have been in the market because I got so much heart-wrenching email from frustrated parents who NEED this product for their bigger kids.

    I started with 1T, 2T, 4T to fit crawling babies through age 4 (potty training age) but now I have sizes all the way to 11 that fits bedwetting pre-teens for overnight. I had to change the grade rule between the 4T and size 5, so effectively I have a toddler size range and a big kid size range. Unfortunately, that means I now have 7 SKUs for every color combination I want in my line!

    I’m pretty glad I bucked the standard cloth diaper sizing (NB, S, M, L, usually), since I guess I’d be at about a 4X!

  7. Jessica says:

    You make such a great point about considering customers’ expectations on sizing, especially when it comes to letters. It seems like a lot of designers are wanting to use XS-XL since it means producing fewer sizes, but then they often want to define those sizes in numbers just as you’ve outlined. This serves as a good reminder of why a designer must give sizing standards very careful consideration.

  8. Don Pezzano says:

    Some valid points once again. Glad I seem to be using the right type- Lettered Sizes. As I make menswear, guys find this easier…they tend to ask for a ‘large’ or ‘X-large’ not a 40″ 42″.

  9. Sarah_H. says:

    I am selling lingerie, and I find it helpful to add the equivalent letter size when the sizing is given in numbers. This is partly because full slips are sized by the bust they should fit, which is a sizing that used to be used for blouses, but is now not used anywhere but slips that I know of. So a 44 full slip is a 1X, etc. (I break it down to 42-44/1X, 46-48/2X 50-52/3X, 54/56 4X…and this is as high as we go.) This saves confusion, since a size 44 Womans size would be about a 7X in dresses or sportswear.

    I do not know about misses sizing, but in buying plus size clothes, I often find both a letter and number designation on the label.

  10. Alizah says:

    And then there’s that other system: the 1-2-3 (sometimes there’s a 4 too) that’s used by some higher end designers like James Perse. To me, that kind of sizing looks kind of boutique-y. Anyone know if I’m I right about this association? I suppose it saves money, much like XS-M-L-XL. Maybe it’s a way of using that same system but trying to appear more “sophisticated”? I don’t know the history of this system, but maybe someone else could enlighten us?

  11. Caryn Ann says:

    I wouldn’t find it confusing… I am normally a medium (8-10) but I read the tag and have noted when a large is 8-10, and I buy accordingly.

  12. Colleen says:

    The Lettered example gives a size range where one size overlaps, ex is XS (0-2) and S is (2-4), so that size 2 is shown for both XS and S.

    Isn’t it usually XS (0-2), S (4-6), etc? without sizes overlapping?

  13. Natasha E says:

    I buy a quite a few garments on Etsy usually cute printed tees ( not words original art ) but nothing bothers me more when their XL is a size 8. I emailed to complain to one girl and her reply was that well she only catered to small people since ALL people in her opinion that ride horses are small. Anyways rant over.

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