Water Calculator for Children

National Academy of Medicine Adequate Intake: 1–3 years: 4 cups (32 oz), 4–8 years: 5 cups (40 oz), 9–13 years: 7–8 cups (56–64 oz), 14–18 years: 8–11 cups (64–88 oz). Our calculator uses weight-based formulas for more precision.

Babies under 6 months should not drink water — breast milk or formula provides all needed hydration. At 6–12 months, small amounts (4–8 oz/day) can be introduced with solid foods. Consult your pediatrician.

Yes. Add 150–250 mL per hour of active play or sports. Offer water before, during, and after activity. Kids often don't recognize thirst until dehydrated, so remind them regularly.

Milk counts toward hydration. Limit juice to 4–6 oz/day for young children (AAP). Water should be the primary beverage. Avoid sodas and sugary drinks.

Signs: dry mouth, few tears when crying, less frequent urination (dry diapers), dark urine, irritability, fatigue, sunken eyes. Severe dehydration is a medical emergency.

Toddlers aged 1–3 years need about 4 cups (32 oz or 1.3 L) of total fluids per day according to the National Academy of Medicine. This includes water, milk, and fluids from food. Our calculator provides a more precise target based on your child's weight.

Children aged 4–8 years need about 5 cups (40 oz or 1.7 L) per day. A 5-year-old weighing about 40 lbs (18 kg) should aim for roughly 1.3–1.7 liters. Use our calculator for an exact recommendation based on weight.

Children aged 9–13 years need 7–8 cups (56–64 oz or 1.7–2.0 L) per day. As children approach puberty, hydration needs increase with body size. Our weight-based calculator gives a more accurate target than generic guidelines.

Teenagers aged 14–18 need 8–11 cups (64–88 oz or 2.0–2.6 L) per day. Boys generally need more than girls due to higher muscle mass. Active teens may need significantly more. Use our calculator for a personalized recommendation.

Make water accessible with a fun bottle, offer water-rich fruits like watermelon and cucumber, set reminders, lead by example by drinking water yourself, and avoid stocking sugary drinks. Start with small amounts and praise them for drinking water.