how to measure, and how to size

Find the narrowest part of your torso, usually an inch above your belly button, and run a soft tape around it. Keep the tape level and snug without pulling. Breathe out normally and do not hold your stomach in, because the garment has to fit the body you actually have all day.

Write the number down before you move on. Measuring twice a week apart gives two different answers, and the first one is usually the honest one.

Measure around the fullest part of your bust with the tape parallel to the floor, wearing the bra you would normally wear underneath or no bra at all. Do not pull it tight.

This is the measurement most people skip, and it is the one that decides whether the top of a bodysuit sits flat or gaps.

Take the larger of the two. A waist can ease into a seamless knit; a bust cannot, and a bodysuit that pulls across the bust will drag the whole garment down.

If you are between sizes on both, size down only if you want the firmest possible hold for a few hours. Size up if you plan to wear it all day.

There is one control level here and it is firm. It holds the midsection noticeably. That is what removes a visible line under something close-cut, and it is the reason to own the garment.

Firm control is comfortable for an evening and tiring for a sixteen-hour day. Any brand telling you otherwise is selling rather than advising. If you want something for all-day wear, order a size up.

Almost all shaping shorts and briefs roll for the same reason. A separate band of elastic is sewn to the top edge, so two fabrics at two different tensions meet at a seam. The band is stiffer than the panel below it, and when you sit down the panel gives while the band does not. It has to fold somewhere, so it folds over itself.

A bodysuit removes the cause instead of resisting it. It hangs from adjustable straps at the shoulder, so there is no waistband at your midsection at all, and nothing there to fold.