If you've ever ordered three sizes of the same dress just to find one that fits, you already know the secret of plus size shopping: sizing is not standardized, and the size on the label means almost nothing without the brand's size chart. A "1X" at one brand can be a "2X" at another and a "16" at a third. The dress doesn't care what number is on the tag. Your measurements do.
This plus size sizing guide pulls together the advice we give in our Auburn boutique fitting room — eight years of helping customers between sizes 12 and 4X figure out what fits, what flatters, and what's actually worth ordering online. By the end of it you'll know how to measure yourself, how to read a size chart with skepticism, and how to choose silhouettes that work with your body instead of against it.
How to take your measurements (the right way)
You need three measurements — bust, waist, and hips — and one accessory: a soft fabric measuring tape. (A metal carpenter's tape will give you a wrong number every time.) Wear thin clothes, ideally a fitted tank and leggings, or your usual undergarments.
Measure yourself for plus size clothing
Bust
Wrap the tape around the fullest part of your bust, keeping it parallel to the floor. Don't pull tight — the tape should sit snug against your body without compressing.
Waist
Find your natural waist, which is usually the narrowest part of your torso, about 1 to 2 inches above the belly button. Wrap the tape there, again parallel to the floor and snug but not tight.
Hips
Stand with your feet together. Wrap the tape around the fullest part of your hips and butt, usually about 7 to 9 inches below your natural waist.
Write it down
Record all three numbers in inches and centimeters. Take them again on a different day to confirm — your numbers can shift 1 to 2 inches based on water retention, time of day, and what you ate yesterday.
Add a fourth if you can
If you're shopping for fitted dresses, also measure your inseam (top of the inner thigh to ankle) and your high bust (just under the armpits, above the breast). These help when the brand has unusually long or short bodice cuts.
How plus size labels actually work
Plus size labels typically come in three formats:
- Numeric sizes (14, 16, 18, 20, 22…). The clearest format, and the one most boutiques and tailored brands use.
- X-sizing (1X, 2X, 3X, 4X). Each "X" usually covers two numeric sizes — 1X is around 14–16, 2X is 18–20, 3X is 22–24, 4X is 26–28. Usually. The exceptions are loud.
- Mixed sizing (XL, XXL, XXXL or "extended"). The least precise; treat with the most suspicion.
The reason this is so messy is that there's no government or industry standard for plus size measurements in the United States. Each brand sets its own chart. Forever 21's 1X is built on different base measurements than Eloquii's 1X, which is different from a contemporary boutique brand's 1X. Trust the inches on the chart, not the letters on the label.
Reading a size chart with skepticism
When you land on a product page, do three things before you add to cart:
- Open the size chart and find your three measurements — bust, waist, hips. The size that fits all three is your starting point.
- If your numbers fall across two sizes, size up. Loose fabric can be taken in by a tailor; tight fabric can rarely be let out, because plus size garments are usually cut close to the seam allowance.
- Read the product description for the fit notes. "Runs small," "very fitted bodice," "stretchy fabric," and "true to size" all mean something specific. A dress with 4-way stretch has very different forgiveness than one in rigid woven cotton.
If the brand publishes garment measurements (the actual width of the dress flat, in inches), even better. Compare those to a dress you already own and love.
Choosing the right cut for your body
There's no "right" silhouette for any size, but here's how the common ones tend to behave:
Fit-and-flare and A-line
The most forgiving silhouettes. They define the smallest part of your waist and then skim over the hips. If you carry weight in your midsection or hips, this is where to start. Most of the dresses in our dresses collection come in fit-and-flare cuts up through 4X.
Bodycon
Bodycon dresses are not off-limits for plus sizes — they just need fabric with real stretch and a smooth interior. Look for "ponte," "scuba knit," or "double-knit jersey" in the description, and avoid stiff cotton blends. We wrote a full guide on how to style a bodycon dress if this is your silhouette.
Jumpsuits
A jumpsuit lives or dies by the inseam and the rise. Plus size jumpsuits often run short in the torso, which causes the crotch to sit too high. Always check the front-rise measurement and add 1 inch to the inseam if you're 5'8" or taller. The stretch jumpsuits we carry are cut with extra rise to handle this issue.
Wrap and faux-wrap dresses
The most universally flattering plus size silhouette in our store. The wrap defines the waist, accommodates a larger bust, and gives you a few inches of adjustability at the tie. If you're between sizes, a wrap is the safest bet.
Empire-waist and babydoll
Skim the body below the bust. Forgiving through the midsection, but can read as "maternity" if the fabric is too loose — opt for ones with a defined bust seam.
Common fit problems and how to fix them
Problem: the bodice fits but the hips are too tight. Size up for the hips and have a tailor take in the bodice. Almost always cheaper than ordering a different dress.
Problem: the bust is gaping. Check whether the dress has a stretch panel or zip. If the cup is too big, it's hard to fix; if the strap or shoulder is too long, a tailor can shorten it for $15–25.
Problem: the dress is the right size but rides up. Usually a length and rise problem rather than a sizing one. Check the brand's "model height" note — if they fit a 5'8" model and you're 5'4" or 5'10", the dress will sit very differently on you.
Problem: the fabric clings to my underwear lines. Shapewear with smooth seams is your friend. So is sizing up if the fabric isn't a 4-way stretch. Cling is usually a fabric weight issue, not a size issue.
Plus size sizing across categories
Different categories cheat differently:
- Dresses: brand sizing is the wild west. Always use the chart.
- Tops: the most consistent across brands — your XL/1X is usually your XL/1X.
- Bottoms (jeans, pants): use waist measurement, ignore the label number. Brand "16" can be a 32" or 36" waist.
- Shapewear: size up. Always.
- Activewear: built with stretch in mind, so it's the most forgiving and the most likely to be true-to-size.
How to shop plus size online without three returns per order
- Measure yourself once a season — your numbers do shift.
- Save the size chart from your favorite brands. Don't trust the "S/M/L/XL" badge in search results.
- Read reviews specifically from people with body shapes near yours. Reviewers who mention "I'm 5'5, 200 lbs, pear shape, ordered size 18" tell you everything in one sentence.
- Skip brands that don't publish a size chart. They're not for you yet.
- Keep one or two known-good brands on rotation. A 2X at a brand you trust is more reliable than experimenting with three new ones every quarter.
For more on keeping the pieces that do fit looking new, see our guide on caring for your boutique pieces. And if you're shopping with us specifically, our chart sits on every product page — the customer support team responds to fit questions within a business day if you'd rather just ask.
Frequently Asked Questions
What size am I if I'm a size 18 in jeans?
An 18 in jeans usually corresponds to a 2X or XXL in plus size tops and dresses, with a hip measurement around 48 to 50 inches and a waist around 38 to 40 inches. Always confirm with the specific brand's size chart because plus size labels are not standardized across stores.
How do I know if I'm between sizes?
If your bust, waist, and hip measurements fall in two adjacent columns on a brand's size chart, you're between sizes. Size up to fit your largest measurement and plan to tailor the rest — letting out a tight seam in plus size garments is usually impossible because there is little seam allowance left in larger sizes.
Why does plus size sizing feel so different from straight sizing?
Plus size patterns are not just straight size patterns scaled up. The proportions through the shoulder, bust, and waist change at larger sizes, and each brand chooses its own base measurements and grading rules. Two brands' size 22s can differ by three inches in the hip and still both be 'correct.'
Should I always size up for plus size?
Not always — but when in doubt between two sizes, sizing up is safer than sizing down for two reasons. Larger garments can be tailored down for $15 to $30, but tight ones often can't be let out. Stretchy fabrics are an exception; trust the size chart and the fabric description together.
Do plus size brands run smaller online versus in-store?
Yes, this is a common complaint. Online plus size lines often source from different manufacturers than in-store private labels, even from the same brand. Check the country-of-origin tag and any 'online-exclusive' wording — those are signals you're looking at a different fit than the in-store version.
Final thought
Plus size sizing has gotten better in the last five years but it's still a long way from "trust the label." The fastest way to a dress you actually love is your own measurements plus skepticism about the chart. Shop with brands that publish real numbers, and walk away from the ones that don't.
When you find a brand whose 2X actually fits like a 2X, save it. That's worth more than any sale.
