Daily Water Intake Calculator for Children
How much water should kids drink each day? Age-based hydration targets for children 4 and up, with parent-friendly guidance.
Prefilled for this goal — adjust anything to match you.
Children dehydrate faster than adults relative to their size — they have a higher surface-area-to-mass ratio, less efficient sweating, and they forget to drink when absorbed in play. School-age kids need roughly 1-1.5 litres of fluids a day as a floor, rising with activity and heat. Mild dehydration is the sneaky culprit behind afternoon grumpiness, headaches, and trouble concentrating in class. Enter your child’s age group in the calculator above for an evidence-based daily target (the calculator uses EFSA and Institute of Medicine reference data). A good habit anchor: a full water bottle in the backpack and one on the desk during homework.
- Age-based targets from EFSA / Institute of Medicine reference data
- Kids often ignore thirst during play — offer water proactively
- Mild dehydration shows up as irritability, headaches, poor focus
- School days need a plan: full bottle at start of day, refill at lunch
Daily Water Intake Calculator for Children — FAQ
Do sports drinks make sense for active kids?
For most childhood activity — an hour of soccer practice, a bike ride — water is enough. Sports drinks earn their place mainly for sustained intense exercise over 60-90 minutes in heat. Otherwise they add sugar without benefit; water plus a fruit snack does the same job.
How can I tell if my child is drinking enough?
Two practical checks: urine should be pale straw colour (dark yellow means drink up), and wet diapers/toilet trips should happen every few hours. Afternoon headaches or sudden irritability that resolves after a drink are common mild-dehydration signs in kids.
Sources: EFSA. Scientific Opinion on Dietary Reference Values for water (EFSA Journal, 2010) — children's adequate intakes · Institute of Medicine. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate (The National Academies Press, 2005) — see our methodology for how they map to the calculation.