I'm a 36C, ordered a Large (light heather gray) and it fits perfectly, not too tight, not to loose.  Better definition than some bras of this style, typical support for this style bra that has no padding but MORE supportive than those that have no definition, just a flat-across-the-front style (the "uni-boob" style). The wide bottom adds to the comfort level, and I like this open back better than the racer back, which I always find more difficult to get on.  I have many of these comfy bras for wearing around home or under baggy sweatshirts, etc, and for $6.76, this one is well worth the money.