It has to be bigger then 3 carats!! I would say at least 4 carats, unless her fingers are REALLY tiny. I love how low the diamond is set as well. I keep going back and forth between this ring and cushion center stone with half moon side stones, not that my boyfriend is even going to propose anytime soon, but I love looking!!!!! But anyway, I think I still love Avril''s set most, I think HAHAHA