Water Intake Calculator
Calculate your personalized daily water goal based on weight, activity, and climate. Get results in liters, glasses, and 500ml bottles.
📖 About Water Intake Calculator
Water constitutes about 60% of the human body and is involved in virtually every physiological process — temperature regulation, nutrient transport, waste elimination, and joint lubrication. The exact amount you need depends on your body size, activity level, climate, diet, and health status. The 35 ml/kg formula is the most widely used clinical guideline.
📜 History
The "8 glasses per day" rule became popular after misinterpretation of a 1945 Food and Nutrition Board statement that actually noted most water needs are met through food. Modern research recommends personalized hydration based on body weight, activity, and climate rather than a fixed daily target.
🎯 Common Uses
- Daily hydration planning
- Athletic performance
- Weight management support
- Hot weather adaptation
- Medical recovery
- Kidney health maintenance
FAQ's
❓ How much water per day?
A general guide is 35 ml per kg of body weight. A 70 kg person needs about 2.45 liters daily. Add 350-600 ml for exercise and 300-600 ml for hot climates.
❓ Does coffee count?
Yes — caffeine causes mild diuresis but net fluid from coffee is still positive. Water, herbal teas, and low-sugar drinks are best for hydration.
❓ Signs of dehydration?
Thirst, dark yellow urine, fatigue, headache, dry mouth, and difficulty concentrating. Aim for pale yellow urine throughout the day.
❓ Should I drink before or after meals?
Drinking 500ml 30 minutes before meals can reduce appetite. Moderate water during meals is fine. After meals, water aids digestion.