I ordered a size 10 based on reviews and the available information and it was too small.  I ordered the next size up and am hoping it's a perfect fit.  This was heavy and very well made and super gorgeous and bamf.  I'm excited to get one that fits well.  I usually wear a medium in fitted shirts that are meant to be tight and large for a somewhat loose fit.  I am 5'3" and 140 lbs.  I do not have dainty arms at all and I have pretty big hips.  I could get size 10 on and zip it up, but it was overall to tight, especially in the arms.