center to center I'm at 9.25", and i wear a 38C bra. In 10 more days I'll have been on HRT for 5 months! That C cup isn't from HRT though, I've had boobs since like 3rd grade lol, I've always been big but my chest has always been perkier than most moobs. The HRT only started actual breast development maybe 2 months ago or so, they've been sore for a while now to the point where I have to wear a sports bra when I go jogging at the park