I originally ordered a 34 C and found them perfect!!!! I ordered another pair at 36 C and they don't support as well, even at the tightest clasp. Stay true to your size and don't contemplate 'staying safe' with the extra inches for your rib case. This bra is super comfy, doesn't dig into your shoulders or your rib cage, and you can bounce around all you like without having your girls hurt!! Best sports bra ever!