Keepin' cozy in plaid ... that pretty much sums up my entire winter, lol!
A great fit, we found it fit true to size with room to layer underneath.
Sara is a size 8 and shown wearing a Medium.
With the garment laying flat, the measurement from armpit to armpit is:
Small 21" // Medium 22.5" // Large 24"
Double the measurement to get the circumference.