My husband is 6'2 and about 185 lbs. He's pretty skinny but a muscular guy. He fills out a size large shirt nicely. First we bought an XL because the lifejacket we bought from Costco 2 years ago was an XL. The Extra Large in this was clearly too big. Then I got smart and measured his chest. He was right at the upper end of the medium on the size chart. I told him and he was adamant that he needed a large so as the good wife I am I bought him the Medium. He tried it on and was happy with the fit. It fits well and is not hard to zip. It looks like he even has an inch or two to grow if he actually goes to the gym as he says he's going to..