I'm kind of confused on size, because I tried the Medium on in the store, and always wear a Medium Koi for top, however, this one is 2" wide on each side, under my arms, sure I can still look cute wearing it, but when I tried it on in the store, it def was not that wide and the small was WAY too small... It is great fabric if you work in a really hot facility, or if you have warmer than average body heat. This shirt is not the longest...so if you have a long torso, it is not meant for you.