Once you've taken your measurements, you will determine your size by using my size charts (scroll down). You can use either inches or centimeters. You need your Chest, Waist and Hips measurements. Be sure and measure at the widest parts. While you are measuring, also measure the desired length so you will have it when you order. Measure down from your shoulders to where you want the apron to stop. There is no right or wrong length it is totally what you want.