Each clothing item includes a sizing chart as the final image in the series. The sizing charts reference body measurements. To get accurate body measurements, please following these instructions: 

Chest: Under the arms and across the shoulder blades with a firm and level tape.
Hip: When standing, measure around the widest part of the hip.
Sleeve length: Relax arm, and measure from the centre of the back of the neck, over the shoulder & down to the outer wrist.
Waist: Measure around your natural waistline, while in your underwear. Keep one finger between the tape and your body for an accurate fit.