Love this bathing suit! I'm a size 18 and will sometimes go down to a 16 or up to a 20. I took both an 18 and 20 to the change room but the 18 bottom was soooo tight and the 20 was still tight. I ended up going into a 22 bottom and purchased a size 18 top (I'm a C40 cup size). Love the support in the top and coverage. Love the underwire in the top, it makes me feel very secure/supported.