What is this Tool?
The Water Intake Calculator helps you determine your optimal daily water requirement based on your body weight, physical activity level, and the climate you live in. Water is essential for virtually every bodily function — from regulating body temperature and transporting nutrients to helping your kidneys remove waste. This calculator uses about 33 ml per kg of body weight as a starting point, then adjusts for activity and heat.
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Frequently Asked Questions
Do coffee and tea count towards water intake?
Yes. Tea and coffee are mostly water, and for people who drink them regularly the mild diuretic effect of caffeine is small, so moderate amounts count towards your daily fluids. Plain water is still the best main drink, and very high caffeine intake isn't a good idea.
Is it possible to drink too much water?
Yes, though it's rare in healthy people. Drinking a very large amount in a short time can dilute the sodium in your blood (hyponatraemia), which can be dangerous. Spread your water through the day and follow your doctor's advice if you have kidney, heart or liver problems or are on fluid limits.
Should I drink water before or after meals?
Either is fine — drinking water with or around meals doesn't harm digestion. Some people find a glass before a meal helps them feel full sooner. What matters most is your total intake through the day.
Why do I still feel thirsty after drinking water?
Heat, heavy sweating, salty or spicy food and some medicines can all make you thirstier. Constant thirst along with frequent urination, tiredness or weight loss can be a sign of a health problem such as diabetes — see a doctor if it persists.
How much water should I drink a day?
A common starting point is about 30–35 ml per kg of body weight. This calculator uses 33 ml per kg, then adjusts for activity and climate. For a 70 kg person with a desk job in a moderate climate, that's about 2.5 litres a day from all drinks.
How many glasses of water should I drink a day?
Divide your daily target by 250 ml. A 2 litre target is 8 glasses; 2.5 litres is 10 glasses. The calculator shows your target in glasses and 1-litre bottles.
Does food count towards water intake?
Yes. Fruit, vegetables, dal, curd, soups and other foods provide a good share of daily water — often estimated at around a fifth of total intake. The calculator's figure is for drinks, so food gives you a little extra buffer.
How much water should I drink in summer?
More. Heat and humidity make you sweat more, so choose the Hot & Humid climate option, which raises the target by 20%. Drink regularly through the day rather than waiting until you feel very thirsty.
How much water should I drink when exercising?
Drink some water before you start, sip during longer or hotter sessions, and replace fluids afterwards. For long, sweaty workouts, drinks with electrolytes can help replace the salt you lose.
What are the signs of dehydration?
Thirst, dark yellow urine, a dry mouth, headache, tiredness and dizziness. Pale straw-coloured urine is a simple sign you're drinking enough. Seek medical help for severe symptoms like confusion or fainting.
Can I drink water at night?
Yes, but if waking up to use the bathroom disturbs your sleep, drink most of your water earlier in the day and have just a small glass before bed.
Should people with kidney or heart problems follow this calculator?
No. Some kidney, heart and liver conditions require fluid limits. If you have one of these conditions or take medicines that affect fluids, follow your doctor's advice instead of this calculator.
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