I am a size 4 in dresses with a 32A bust and a 27.5" waist. The chest area and upper waist is quite snug for me because my ribcage is larger, so it fits just exactly once zipped up. The actual cups fit very well and can probably fit between an A-B cup. I say it fits in between an xs and a s. It's floor length and works best with heels, and I am 5'5'' and if I don't wear platforms, the dress will graze the floor.