I bought the top in a 2x because I read other reviews that said the cups run small. I am a 36dd and it fit perfectly, I would think going a size up would be too large at that point. The style of the top is very flattering and I love how the straps are removable to give options on wearing the top. The flutter sleeves arent the most practical for swimming, but I imagine this would be more for wearing around the beach. I also bought an x in the matching bottom and those fit perfectly as well, I am usually a 14 in bottoms. I got lucky in that both fit perfectly on the top and bottom, but I imagine it would be a bit oft trial and error for other people with how the sizing runs on these items. Overall very happy with the purchase, and thinking of buying the same set in the other colour as well!