Doctor's Guideline is 1 kg: 5 oz - 6 oz. So if your child is 5 kg now, he would be able to drink 25 - 30oz per day. But breastmilk & formula can be different, so there's no hard rule. As long as he's gaining weight (about 0.2kg per week) and has sufficient wet nappies, he should be OK. :loveliness: