Shapewear and waist trainers are sized off your body, not your usual jeans size — which means the tape measure does more work here than the label ever will. Five quiet minutes with a soft measuring tape is the difference between a piece that smooths comfortably and one you’re tugging at by lunchtime.
What You'll Need
A soft, flexible measuring tape (not a metal one from the toolbox), a mirror if you want to check it’s level, and a few minutes in close-fitting underwear or clothing. Stand naturally — don’t suck in, don’t stand extra tall, don’t hold your breath. You’re measuring the body you’ll actually be wearing the piece on, not a held-in version of it.
The Three Measurements That Matter
Natural Waist
Find the natural crease when you bend gently to your side — that’s usually just above your belly button, not at your pants line. Wrap the tape around, parallel to the floor, snug but not pulled tight enough to indent your skin.
Upper Belly (Under-Bust to Navel)
This is the measurement most people skip, and the one that matters most if you’re choosing a waist trainer with a taller panel. Measure around the fullest part of your upper abdomen, roughly midway between your bust and your natural waist.
Hip / Widest Point
Stand with your feet together and measure around the widest part of your hips and seat — usually several inches below your natural waist. This number matters most for full bodysuits and longer waist trainers that extend past the hip.
Mistakes That Throw Off Your Numbers
- Measuring over bulky clothing instead of close-fitting layers
- Pulling the tape tight enough to compress skin, which shrinks your real number
- Measuring right after a big meal or at the end of a long day, when your waist naturally sits a little fuller
- Using your usual clothing size instead of your actual measurements — the two rarely match exactly
Matching Your Numbers to a Size
Once you have your waist, upper belly, and hip numbers, check them against the size chart on the product page rather than your usual size in dresses or jeans — shapewear runs on its own scale. If you land between two sizes, choose the larger size for a more relaxed fit; a slightly looser waist trainer still smooths, and it’s one you’ll actually reach for again tomorrow.
For structured, adjustable support, the MemoryLine 17-Bone Waist Shaper uses adjustable straps and multiple hook rows, so it has some built-in room to fine-tune as you settle into the fit. If your waist and upper belly numbers are noticeably different from each other, the CoreLine Sectional Waist Corset’s three-panel construction is built to flex across both areas instead of treating your torso as one straight measurement.
Re-Measure as Your Body Changes
Weight fluctuation, workouts, and even the time of month can shift your numbers slightly — that’s normal, not a sizing failure. If a well-fitted piece suddenly feels tighter or looser than usual, it’s worth re-measuring rather than assuming something’s wrong with the garment.
Ready to shop your numbers? Browse the Shapewear collection for waist trainers, cinchers, and shaping bodysuits in a range of sizes.