Corset are sized by waist size. So the waist measurement is the most important thing when sizing for a corset. Boned corsets are designed to be ordered 2 or 3 inches under your natural waist measurement. For example, if the measurement around the narrowest part of your relaxed waist is 30/31", you would typically order your corset in size 28" with semi lacing back open. Corsets are designed to cinch the waist and lift the breasts. Lacing in the back allows the corset to be adjusted for comfort. Size Details: size S: 32"-34" in Bust, 24"-26" in Waist, Suitable for Cup A-B Size M: 34"-36" in Bust, 26"-28" in Waist, Suitable for Cup B-C Size L: 36"-38" in Bust, 28"-30" in Waist, Suitable for Cup B-C Size XL: 38"-40" in Bust, 30"-32" in Waist, Suitable for Cup B-C Size XXL: 40"-42" in Bust, 32"-34" in Waist, Suitable for Cup B-D