Water Intake
The Water Intake Calculator estimates how much water you should drink each day based on your body weight, activity level, and climate - a simple guide to staying properly hydrated.
How much water do you need?
A common guideline is roughly 30–35 ml of water per kilogram of body weight, adjusted upward for exercise and hot weather. The calculator applies that logic to your details, so a 70 kg moderately active person might land around 2.4–2.8 litres a day, including water from food and other drinks.
Factors that raise your needs
- Exercise - replace fluids lost through sweat, often 0.5–1 litre extra per hour of activity.
- Hot or humid climate - increases sweating and evaporation.
- Pregnancy or breastfeeding - raises daily requirements.
Thirst and pale-yellow urine are good everyday indicators. This is general guidance, not medical advice - check with a doctor if you have a condition affecting fluid balance.
Frequently Asked Questions
How many litres of water should I drink a day?
A rough guide is 30-35 ml per kg of body weight, so most adults need about 2-3 litres daily, more with exercise or heat.
Does water from food and tea count?
Yes. Food, tea, coffee, and other drinks all contribute to your daily fluid intake, not just plain water.
How do I know if I am drinking enough?
Pale-yellow urine and rarely feeling thirsty are good signs. Dark urine and persistent thirst suggest you need more.
Can I drink too much water?
Rarely, but drinking excessive amounts in a short time can dilute blood sodium (hyponatremia). Spread intake through the day.
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