In the Chart below
– Choose the cup size
– Follow the row horizontally, to find the bra band size
– Follow this column vertically down to the breast form (external Prosthesis), the number in this square gives you the prosthesis size.
– This is a guide for the size of external prosthesis, however for a perfect fit a size up or down may be needed
Click on Image for larger view
Source : www.icancare.org