I own two of these, one in Deep Wine, size large, and one in Blue Topaz, size medium. I am normally right on the line between a 10 and a 12.  The medium is perfect if all I want to layer underneath is a light sweater or sweatshirt--perfect sleeve length, range of motion in shoulders, etc.  The large allows me more room for layering, but the sleeves are long and bunch up, and there is far more shoulder room than I need. I highly recommend this jacket, but if at all possible try it on wearing what you would be most likely to layer under it.  Or just buy two sizes like I did--I love this jacket and have no regrets about buying two!! Both colors are beautiful, the Deep Wine is very dark and subtle and the Blue Topaz is a bright, almost turquoise blue. It is very warm and even in the smaller size, is easier to layer with than most other ladies jackets. The sandstone is surprisingly soft right off the bat and the sherpa lining is wonderful.  I also like that the zipper is large and heavy duty, for that matter the entire jacket is very sturdy especially for being so cute looking.