Multiply your baby's weight by 2.5 oz. So if your baby weighs 8 pounds, you'll give him about 20 ounces of formula in a 24-hour period. If he weighs 10 pounds, he should drink about 25 ounces in a 24-hour period. This is only a general rule of thumb. Just as your appetite varies with each meal, your baby isn't going to take exactly the same amount at each feeding. Don't force your baby to finish the bottle, even if there's only a little bit left. And keep track of your newborn's wet diapers: At least six a day should be soaked through with clear to pale yellow urine.
And baby may be hungrier than usual during growth spurts — which typically occur ten to 14 days after birth and at 3 weeks, 6 weeks, 3 months, and 6 months.