I originally purchased (per recommendation from a Carhartt website live chat) a 2xl-5xl to fit my 2xl Carhartt coat....wrong!  The middle snaps were way too far apart for my coat.  Reordered the smaller size (sm-xl) and the fit is much better but still just a tad big.  I will work on the hood in the dryer in high heat and hope I get some shrinkage.  The hood itself is nice and big and fits well on my large head......I can easily wear a watch cap and hoodie underneath the hood.