I struggled with this purchase because I could not figure out what size to get.  Nowhere could I find a chart that would guide me to selecting a size 'medium' for a 36C (for example).  Everyone is right that these run small.  I am a 36C and this medium is quite tight on me.  Since it's a sports bra, that's probably a good thing, because no jiggle is happening here!  But if I wanted to just wear it as a regular everyday bra, it'd feel too small.  It is good quality, as you'd expect from Champion.