To achieve your desired fit, we recommend first selecting the size of your outer layer based on your usual US clothing size. Then select the size of your support based on your usual cup size. Note that our fabrics are stretchy, so if you are on the cusp, size down for a tighter fit and less coverage, or size up for a relaxed fit and more coverage. All measurements are in inches, and the range reflects the widths and lengths of the garment while laid flat and stretched. Feel free to email us at firstname.lastname@example.org with any fit questions.