How to measure dress size for the most flattering fit. Bust size: Measure around your chest, at the fullest point of the bust (not under the bust). Waist size: While standing up straight, bend at the waist to one side. The crease that forms is where your natural waist is located; measure there. Hip size: Standing with your feet together, measure around the fullest part of the hips. Hollow-to-Hem Measurement (Length). Your hollow-to-hem measurement is determined by measuring from the center of your collarbone (hollow) to the bottom (hem) of your dress.