Use the sizing in the picture of the product; I  am 42-38-44 and the size 20 fit well. Absolutely fantastic jacket for work. Lightweight and machine washable. I bought it in maroon and black. It looks beautiful and keeps me warm. Only concern is since I am short, the sleeves are a little long. Plus, real pockets!!!! I like it so much I am waiting until they have the white in my size to purchase a third.