How to Size Shapewear When You're Between Sizes (and Why Your Dress Size Doesn't Carry Over)
Last reviewed June 2026. This guide is for general styling and information only and is not medical advice. Talk to a healthcare professional before using compression garments postpartum or if you have a health condition.
The short answer
Between two shapewear sizes, size up. A larger size at light-to-medium compression smooths cleanly; a smaller one digs, rolls, and bulges at the edges. And don't assume your dress size transfers — brands size shapewear to body measurements, not garment sizes, so measure your bust, waist, and hips and read each brand's chart.
Below: how to take the three measurements that decide fit, why the dress-size habit fails, and when up vs down is the rare exception.
Measure for your body, not your wardrobe
Shapewear charts are built from body circumferences, so the number that matters is your tape measure, not the tag in your jeans. Measure with the tape parallel to the floor and comfortably snug — not digging in, not hanging loose (Sew Liberated measurement guide):
- Bust: around the fullest part, tape level all the way around.
- Waist: the narrowest part of your torso, usually just above the hip bones — bend to one side and the crease that forms marks it.
- Hips: the fullest circumference through the seat, which is typically about 7–10 inches (18–25 cm) below the waist — measure the fullest point, not the hip bone.
That last point trips up many shoppers: measuring the hip too high underestimates the number and lands you in something too tight across the back. Measuring at the fullest part of the seat — not at the hip bone — is the convention shapewear charts assume. Your measurements set the size; your height then decides the cut, which is its own question covered in shapewear for petite vs tall.
Why your dress size doesn't carry over
Two reasons. First, women's apparel sizing isn't standardized between brands — a "medium" or a "size 10" can differ by inches from one label to the next, because there is no enforced national size standard for women's ready-to-wear; manufacturers set their own. So even your dress size isn't a fixed body fact across brands, let alone a reliable input for a different garment category. Second, shapewear is engineered to compress and redistribute, so its sizing is mapped to raw measurements rather than to the ease built into everyday clothes. The practical consequence: a piece labeled the same "L" as your favorite dress can be a full size off for your body. Read the brand's measurement chart every time — the same discipline behind choosing shapewear by your measurements rather than your dress size.
Between sizes: up vs down
When your measurements straddle two sizes, the default is up. Here's the decision in one view:
| Situation | Choose | Why |
|---|---|---|
| Between sizes, want all-day comfort | Size up | Light/medium smoothing without digging, rolling, or marks |
| Measurements split (e.g. M waist, L hips) | Size to the LARGER measurement | The bigger zone sets the size; a too-small panel there bulges and rolls |
| Between sizes, very firm "occasion" piece | Still size up | Firm fabric already compresses; the smaller size just gets painful |
| Garment runs large per reviews | Size to chart first, adjust only on real feedback | Reviews help, but the brand chart is the primary input |
The reason up wins is mechanical: a correctly sized piece smooths without a fight, while a too-small one compresses the wrong zones, creates bulges at the seams, and can make breathing genuinely uncomfortable — and it never sculpts better than your correct size does. Watch for the warning signs that you've gone too small: you can't take a full relaxed breath sitting down, fabric edges leave deep red marks, the garment rolls at the waist or slides up the thigh, or a bulge appears just above or below the compressed area. Any of those means go up a size — they are signs to fix the fit, not signs the garment is working.
An honest take
Sizing is the whole game, and the honest rule is unglamorous: buy the size your measurements say, and when in doubt, up. Shapewear smooths your line while you wear it — it does not reshape your body, change your measurements, or make a smaller size fit by force. If a piece leaves marks, goes numb, or makes a full breath hard, size up or choose lighter shaping. When you want to compare how a brand's chart maps to real cuts, Shapeshe lists size guidance alongside its styles, which makes it easier to match your measurements to a piece. Fit, not force, is what looks smooth.
Disclosure: The Shapely Edit is reader-supported and may earn a commission from some links. This article is styling and general information, not medical advice.