How water intake calculator works
Daily water needs depend mostly on body weight, with more added for exercise and a small adjustment for climate. A common rule of thumb is about 35 millilitres per kilogram of body weight per day, plus extra for activity and a boost for hot weather.
This calculator uses that rule: 35 ml per kg of body weight, plus about 12 ml for every minute of exercise, then a 10% increase for a hot climate and a 5% reduction for a cold climate. It reports the result in millilitres, litres, fluid ounces, and cups so you can use whichever unit you prefer.
Enter your weight (kg or lb), your daily exercise minutes, and your climate. The tool returns the recommended daily intake. This is a rough guideline; actual needs vary with diet, humidity, health, and pregnancy — drink to thirst and consult a doctor for personal advice.