This calculator estimates your daily water needs from your body weight and exercise time, using a common clinical heuristic and the U.S. National Academies adequate-intake figures as a reference.
Sample input: Weight (kg): 70, Daily exercise (minutes): 45
Daily water target: 3.7 (Estimated fluid needs)
Aim for roughly 3.7 liters (3710 ml, about 15 cups) of water per day based on your body weight and activity. Drink more in hot weather or illness.
We start from about 35 ml of water per kilogram of body weight, then add roughly 12 ml per kilogram for each 30 minutes of exercise. This is a widely used clinical heuristic for fluid needs.
The U.S. National Academies set adequate total water intake at about 3.7 liters per day for men and 2.7 liters per day for women, including water from food and other beverages, so drinking-water targets are usually lower.
Yes. About 20 percent of daily water typically comes from food, especially fruits and vegetables. The plain-water target from this tool is a guideline for fluids you drink.
Hot or humid weather, high altitude, fever, vomiting, diarrhea, pregnancy, and breastfeeding all increase fluid needs. Use thirst and urine color as practical day-to-day guides.