【How-to】How much is half a gallon in oz

Children. … Children between 4 and 8 years old should drink 40 ounces per day, or 5 cups. This amount increases to 56 to 64 ounces, or 7 to 8 cups, by ages 9 to 13. For ages 14 to 18, the recommended water intake is 64 to 88 ounces, or 8 to 11 cups.