I bought this because it's one of the few E/F swimsuit options available. I wear a 36DDD(F) and based on the size charts I should be a 16 but since 18 was the smallest option available, I went with that and it worked. Luckily it has some adjustability in the back so I just put it on the tightest one and it worked okay. I have a 35 inch waist and 47 inch hips, so theoretically I would be between a 16 and 18 (which the size chart says is for 39in waist). I went with the 18 to accommodate my hips, thinking they would be a little loose with 4 extra inches in the waist. Not so! They were very tight. The black mesh on the sides is really cute, but the straps that go across are tight and fat bulges out around them in a very unattractive way. I will be exchanging up for a 20 and hope that works out!