this runs large. the jacket has stretch but even without the stretch its too big. I am a size 14-16 and purchased both a xl and 1x. both are huge. i tend to order up to accomodate my broad shoulders but in this case its not needed. boxy shape, stretch and overall larger cut means i can go to a large. i can see women with smaller shoulders/chest might even be able to size down given the cut and stretch.. I will order again and try a large. jacket itself is well made and will go with many outfits.