Im a 40C and based on reviews I purchased the XL size. Im so happy with the results! I originally bought these for running because my other sports bras offered no support. Ive got to say, I will look for these in my drawer and use them before all my other ones. I use them for walking, jogging, and they're comfortable enough to wear all day. They come with a removable insert but I found that I can keep them in and they won't bunch or fold awkwardly like other sport bras. So glad I found them!!!