I went through a few sizes before I found the one I wanted. I normally wear a medium to a large shirt depending on the fit around the bust. For this jacket I was looking for a more loose, draped look so it was comfortable and casual to work in. I initially ordered a lrg, then accidentally ordered a lrg again. The large fit, but it was snug around my shoulder and bust, with the sleeves being just a little shorter than I wanted. It didn’t have the casual look and feel to it. The x-lrg fits exactly how I want. Loose and casual, the sleeve length is long enough and loose enough that I can scrunch it up to my elbows.
It is maybe not the most flattering blazer on me since I’m a curvy girl and the loose fit makes me look boxy, but I intend to get it fitted and see how it goes.