I dont go so much by the weight and height measurements for the clothes, because Erica is still in 0-3. We have put a couple 3-6 mo onesies on her, and they are still too big, but I think in the next few weeks she might move into them... In some brands. I've been able to tell if they are getting small by if the onesie is kinda snug to snap at the bottom. She has never really filled them out width wise, just length. You will figure it out tho if the clothes are too small, dont worry! =)