Your Guide to Plus-Size Sizing

Do you know the difference between an XL and a 1X? Sizing can be confusing—especially in plus, so we’re breaking down everything you need to know when shopping to find the right fit for you.

  • 486

Is there a difference between an XXL and a 2X? If you can find clothes that fit in both the straight size section and the plus-size section, which one should you shop? We’ve heard these questions and so many more like them from our community members because when it comes to sizing, things can get really confusing. And when it comes to plus-size sizing? Not only are there more limited options to choose from, but the sizing confusion increases!

With every brand’s fit varying slightly, it’s hard to know exactly what the cause of this size discrepancy is. These types of fit frustrations are among the many reasons Dia&Co was founded. To get a better understanding of how sizing works in both straight and plus sizes, we sat down with Dia&Co’s own designer Marita Aikonen.

Why does every brand’s size 14 fit a little differently?

This can be an extremely frustrating experience—especially when it comes to online shopping as you order the size you expect to fit and when you finally get the chance to try it on, you discover it’s not the right size. The truth is that every brand’s fit is unique. Each brand uses a fit model, a real human being with a fairly proportionate body type, to try samples on and adjust fit to.

With straight sizes, the fit model is generally a size 8 or a medium. With plus sizes, the fit model is generally a size 18 or a 2X. For this reason, samples are created generally in sizes 8 or 18 to be fitted on the fit mode. Because size 8 is in the middle of the size run for straight sizes and size 18 is in the middle of the size run for plus sizes, brands will grade up and down to determine the measurements of all of the sizes smaller and larger than the sample size.

Brands choose their fit models thoughtfully and they pick out a model based on her shape, with their target customer’s shape in mind. The goal, of course, is to get the most universal fit, so finding a fit model that is fairly proportionate is important. But, every designer and every fit technician will fit differently and will have a different intent. However, if the size 2X fit model is more bottom-heavy it could mean that the fit of the brand’s bottoms will be roomier and the tops will be a bit smaller. Therefore, there is true size discrepancy from one brand to the next and even within different categories of the same brand. In some brands, the knits (stretchier fabric that have give) will fit much larger than the wovens (stiffer fabric that has no stretch or give at all).

Straight sizes versus plus sizes chart

How does straight sizing differ from plus sizing? 

In straight sizes, like in plus, garments are fitted on the sample size and then all of the sizes smaller and larger are graded up or down. So, a size M (generally a size 8/10) will be graded up by adding additional fabric evenly for a size L. If an inch is being added between a size M and L, then an inch will be subtracted from a size M to a size S. However, body types aren’t necessarily exactly that much larger or smaller.

When you take curves and proportions into account: in order to get the perfect fit, extra fabric will be required in specific places but not everywhere. For example, a size XXL blouse may have 3 extra inches added to the torso area but doesn’t need 3 extra inches in length on the sleeve. As our bodies get larger, our limbs don’t get longer. A woman that wears a size XXL will certainly be curvier than a woman that wears a size M, but the fit does not take those curves into consideration since the fit model used was not the curvier figure of a size XXL. If you are wearing a size XXL, you may be wearing an item that is oversized in the armhole and neckline and that may have too long sleeves. This is because the garment has been fitted to be a bit wider everywhere, but it likely is not wider (and narrower) in all the right places.

In plus sizes, however, the difference between sizes is not the same from size 0X (or 12) to a 5X (or 30/32). Instead, the difference gets a bit larger as the sizes get larger. Fit models for plus are generally a size 2X or 18/20, meaning that this fit model definitely has a curvier figure. Because curves are taken into account in plus-size sizing, you will notice a difference in fit. Plus sizes generally give a bit more room in the armhole, but the sleeve won’t be too long. As bodies get larger, they don’t also get taller and longer. This is, of course, common sense, but it’s not necessarily considered when a brand grades up from their straight-size fit model which is why sleeve lengths tend to be longer in straight sizes than in plus.

holiday plus size skinny jeans

Why is denim particularly hard to find the right fit?

In plus sizes, denim is fit very differently than in straight sizes. There is a lot more room in the rise, back, and crotch area to make room for the belly, hips, butt, and thighs. Sometimes, denim in sizes 16-22 (which for some retailers is the largest of the straight sizes) is graded up and down based on the sample size and other times brands will use plus-size grading for those sizes. Each brand is unique, which is part of why denim can be such a tricky fit.



Is a 1X and a XL the same? What about a 14 and a 14W?

Straight sizes generally go from a size 0-14 (or an XS – L), but in some cases, they’ll go from a 0-22. In alpha sizing, this would be a size XXS-XXL.  At the same time, that same brand may carry 0X-5X plus sizes, which would be a size 12-32. That means there is a lot of overlap and many plus-size women who wear sizes 14-22 will be able to wear styles from the straight-size section or the plus-size section. While a size XL is designed to fit a size 16/18, she may prefer to wear a size 1X which equates to a size 14/16. This is because the plus-size section was designed with curves in mind. That means the arms will likely fit much better, the neckline will lay better, and the sleeves won’t be too long.

In plus, alpha sizes are labeled 0X, 1X, 2X, 3X, 4X, and 5X. Numerical sizes are often labeled as 14W, 16W, 18W, and so on. The W is for Women’s, which is another way of saying plus-size. The “W” sizes are fitted for plus size specifically, whereas sizes like 14 and 16 in the same brand were likely fitted on a straight-size fit model.

If you fit into both straight and plus sizes at stores like Target and Old Navy, you may want to do a test for yourself and try on your size in both sections to get an understanding of the difference in fit. If you’re placing an order online and don’t want to order two of the same item from each section, the safe bet is to go with the plus size.



Just because I wear a size 16 in dresses doesn’t mean I can’t wear a sweatshirt in a 3X, right?

First off, it’s important to learn your size even though that may differ from brand to brand. Once you understand your size in bottoms, tops, dresses, and your bra size, you can begin experimenting. Fit is personal, and sometimes fit is style. If you want to play around with rocking an oversized T-shirt as a dress or a knit top in a couple sizes too small and wear it as a crop top, go for it! What’s important is that you are defining your personal style and enjoying expressing yourself. But, if you don’t know how to begin, it’ll be hard to play with proportion and experiment with different sizes.


Wondering about your Dia&Co size? Check out our size chart or seek out the help of one of our expert stylists by getting a Dia Box today!