Common sizes for women's underwear are extra small, small, medium and large. Additional sizes for women's panties are extra large, double extra large and triple extra large.
Size extra small women's underwear generally fit a waist that measures 23 to 24 inches and hips that measure 33 to 34 inches. Size small panties fit a waist that is 25 to 26 inches and hips that are 35 to 36 inches. A size medium is made for a waist that measures 27 to 28 inches and hips that are 37 to 38 inches. The large size fits waists that are 29 to 30 inches and hips that are 39 to 40 inches.