How do you choose period underwear size?

Measure your waist at the narrowest point and your hips at the fullest point, then match both numbers to the brand's size chart. If you fall between sizes, size up for comfort and to keep the leak-proof layer sitting correctly.

A good fit should feel snug and secure but not tight. Different styles — bikini, brief, high-waist — fit a little differently, so check the chart for each style.