Great dress to be covered, but sexy! I go between a M or L with FN dresses. I go up to a L with fitted dresses bc I have a mama pooch. Got this in a L and love it. It’s slightly loose at the top (around the hole), but I’m thicker at the bottom, so it works. I’m 5’7, 165 lbs. Tall/ slender build- smaller on top (small C) and thicker with long legs on the bottom. It’s very stretchy and thick material. If you’re between sizes, you’re safe to go either way depending on a more fitted or slightly looser fit. The dress looks exactly as pictured and I love the pull string detail. Great to show off pretty legs!