To choose the correct size for you, measure your body as follows:
Chest :
Measure around the fullest part, place the tape close under the arms and make sure the tape is flat across the back and parallel to the floor.
Waist:
Measure around the narrowest point of your waist, keeping the tape parallel to the floor.
Hip
Stand with feet together and measure around the fullest point of your hip, keeping the tape parallel to the floor.
Robyn Hunter –
Cap is One Size fits all