Hydration Calculator – Calculate daily water needs based on weight and activity
The hydration calculator determines daily fluid requirements based on weight, activity level, climate, and health conditions. See recommended water amounts in liters and fluid ounces.
Basic recommendation is about 35ml of water per kilogram of body weight daily. Exercise, heat, breastfeeding, and certain medical conditions increase requirements. The calculator considers these factors for personalized recommendations.
How much water should you drink per day?
Health authorities recommend women consume 2.7 liters and men 3.7 liters of fluids daily from all sources (food + drinks). A 150 lb person needs about 2.5 liters. One hour of vigorous exercise increases needs by 0.5–1 liter. Caffeine and alcohol increase fluid loss and raise requirements.
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Browse all tools →The hydration calculator estimates your daily water needs based on weight and activity level. A useful tool for anyone wanting to ensure adequate fluid intake.
Enter your weight and activity level, and the calculator will estimate your daily fluid needs in liters.
- Estimate daily water needs based on body weight.
- Account for the impact of exercise, hot weather, and other factors on fluid requirements.
- See recommended fluid amounts as glasses or bottles.
Fluid needs are individual and vary daily depending on conditions.
- General guideline is about 30-35 ml per kilogram of body weight per day.
- Exercise, heat, and illness increase fluid requirements.
- Food provides a significant portion of daily fluid intake – fruits and vegetables contain lots of water.
Adequate fluid intake is important, but excessive drinking can also be harmful.
- Thirst is a reliable indicator of fluid needs for most people.
- Certain medical conditions and medications can affect fluid requirements – consult your doctor.
- The calculator provides estimates – it doesn't replace guidance from healthcare professionals.