I normally wear a 3X, bought a 3X, the fit is very comfortable. I have room to wear things underneath and it's just super comfy. It seems really warm but I haven't been in very cold weather yet. I also I'm curious to see how water resistant it might be, so I will update on that as well. The downside is it is slightly garbage bag like, but I think that's kind of how these things are especially if you buy black. I'm not really deducting from it because I don't think a different brand of the same style jacket would look LESS  like a garbage bag LOL I'm hoping this will serve me well on my Alaskan cruise!