I am wearing the light birch color here in this video in a size large. My brown colored one that I own is also a size large. I did try on a medium in store and it fits in the arms and the bust and I was able to zip up the jacket however the waist was definitely tighter than the size large. If you want a looser fit stick to your true size if you would like a more snug fit, size down one. The sleeves are perfect because they actually stay in place when you pull them up as well. LTKOver40 LTKMidsize LTKdayinmylife