Water Calculator Home Water Calculator Staying hydrated starts with knowing your number. Enter your weight to get a personalized daily water intake range in ounces and liters. An OHO Seminars tool. Water Calculator Choose your measurement of weight: * PoundsKilograms Enter Your Weight Lowest amount of water to drink in ounces: Highest amount of water to drink in ounces: Lowest amount of water to drink in liters: Highest amount of water to drink in liters: Submit If you are human, leave this field blank.