Daily Hydration Requirement
Estimate daily water intake based on body weight, physical activity, and climate conditions. Based on EFSA (European Food Safety Authority, 2010) recommendations of ~35 mL/kg/day.
Results
What is it?
Estimates your daily water needs using the EFSA (European Food Safety Authority, 2010) baseline of 35 mL per kilogram of body weight, then adjusts for physical activity and climate. Adequate hydration supports thermoregulation, nutrient transport, and cognitive function.
How to use
Enter your body weight, select your typical activity level, and choose your climate. The calculator adds fixed mL bonuses for exercise (500 mL moderate, 1000 mL intense) and hot/humid conditions (500 mL) on top of the 35 mL/kg baseline.
Example scenario
A 75 kg person doing moderate exercise in a temperate climate: baseline = 75 × 35 = 2625 mL, plus 500 mL for activity = 3125 mL (≈ 3.1 L or about 13 cups). In hot weather, add another 500 mL for a total of 3625 mL.
Pro tip
These are starting estimates — actual needs vary with sweat rate, altitude, and dietary water content. A practical check is urine color: pale straw indicates good hydration, while dark yellow suggests you need more fluids.