It was not necessary to go up a size, the coat is already large, but it is good because I can wear layers under it to stay extra warm. However, that and the coziness of it is all I can say good about it. The zipper is AWFUL. It gets stuck and is very hard to unzip or zip up. Somebody must have been on something when they made this jacket. Don't order, it's nice and warm, but if you can't get into it or out, what is the point?See full review