Hydration Calculator
Calculate how much water you should drink per day based on your weight, age, activity level and climate.
Bottled water picks
Once you know your daily target, pair it with a mineral water that supports your goals — electrolyte support for sport, low sodium for blood pressure, or a mineral-rich water for bone and muscle function.
How the calculation works
Adult baseline: 35 ml of water per kilogram of body weight (Geneva Foundation for Medical Education guidance). Older adults (55+) use ~30 ml/kg; growing teens use ~40 ml/kg.
Activity adds 350–700 ml. Warm or hot climates add another 250–500 ml. The result is a practical target — adjust upward when training hard, in altitude, while breastfeeding, or any time urine runs darker than pale straw.
