The Underwear Size Guide

Underwear sizing runs on two numbers, waist and hip, with the hip in charge. This hub collects the tools and fixes: the calculator for your size, the shapewear rules that differ from regular underwear, and the fit-problem fixes for rolling, riding and digging.

• Panty size calculator: waist + hip to size, with the size-up logic built in.
• Shapewear calculator: compression levels and the never-size-down rule.
• Underwear fit problems: rolling waistbands, riding backs, dig lines, solved.

The three rules that prevent most problems

Size to the hip, always: the waistband stretches to fit a range of waists, but nothing stretches a garment over hips it was not cut for. Between sizes, go up: elastic forgives down a size gracefully and punishes up a size with rolling and lines. And match the cut to the outfit rather than forcing one cut everywhere: briefs at the natural waist, hipsters at mid-hip and thongs beneath fitted clothes each solve a different problem well.

Fabric honesty

Cotton breathes and forgives, microfiber disappears under knits, lace behaves at the waist but rolls at tight leg openings unless edged with soft elastic. Seamless one-size stretch works within a narrow range of bodies and compresses unpredictably outside it; sized garments in S through 4X fit more people better, which is the same lesson bras teach.