Striped Long Button-down Shirt

Using a soft measuring tape, measure your bust at the widest part.

Measure your waist at the narrowest part. That is usually around the same height as your belly button. At this stage, the measuring tape should not be too tight and should allow you to be comfortable.

Measure your hips at the widest part

To figure out the best one-piece swimsuit size for you, the circular measurement of your torso is the best tool there is! The measuring tape should go all around your body, including your front and your back. This measurement is taken at a slight angle, from the crotch to the shoulder, going over the breast. It takes into account the length and depth of the body to allow you to be fully comfortable in your swimsuit.