Do what everyone else says - buy 2 sizes too big.  Ignore the 1 person that said not to and listen to the 50 that say 'go big'.  If you even THINK about ordering your perceived size in this shirt ... you will be angry when you either have to ship it back - or pass it down to your 5th grade son.  So, heed what I say.  The shirt is friggen awesome ... I absolutely LOVE IT.  If I had not gained 15 pounds, I would be wearing it right now - even though it's winter time.  I completely recommend this purchase and am thrilled with it and know that it will provide me with years of service.