I wear a size 16 jacket/coat and have the Carhartt women's detroit jacket in a size X-L; I'm average height with broad shoulders and rather big busted (not to be TMI, I wear a size D cup).  I read the reviews that said this vest ran large and to order a size down from the usual.  So I followed that advice and ordered this vest in a size Large, it was too small, it was too tight in the bust and I would only be able to wear a not so thick turtleneck with it.  Since amazon was out of this color or another color I wanted, I returned it and went with an X-L from another amazon dealer.  The XL is a perfect fit, enough room to fit a heavy sweatshirt or sweater underneath, warm and not boxy.  This vest is perfect for my job working with leash aggressive/frustrated greeter dogs where things can get dirty and I have been pawed (I had one jump on me and her claws ripped less quality fabric).  True to my 20+ years experience with Carhartt-the cotton is rugged, washes well, is warm and sturdy.  It's nice to have some color options that add some spice.  It has passed on paw/claw test with flying colors.