Water intake calculator
How much water to drink each day, in litres and glasses.
Water to drink a day
2.8 litres
About 11 glasses of 250 ml
- For your body weight
- 2.5 litres
- For exercise
- + 0.4 litres
- Total a day
- 2.8 litres
- In 250 ml glasses
- 11
About 35 ml per kg of body weight, plus about 350 ml for every 30 minutes of exercise. This includes water from tea, milk, soups and juicy fruit, not just plain water. People with kidney, heart or liver conditions should follow their doctor’s advice.
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How to calculate your daily water intake
- 1
Enter your weight.
- 2
Add how many minutes you exercise a day.
- 3
Switch on hot weather if it applies, and choose pregnancy or breastfeeding if relevant.
- 4
See your daily water in litres and 250 ml glasses.
How much water you need
Your body loses water all day through breathing, sweat and urine, and loses more when you exercise or the weather is hot. The calculator estimates how much to drink each day from your weight, exercise and climate, with extra for pregnancy and breastfeeding, and shows it in litres and 250 ml glasses.
A daily water intake calculator: how much water should I drink a day?
How it’s worked out
- Body weight: about 35 ml per kg. At 60 kg that’s 2.1 litres; at 70 kg, 2.45 litres.
- Exercise: about 350 ml for every 30 minutes of activity.
- Hot or humid weather: about 500 ml more, which matters across much of India and the Gulf for most of the year.
- Pregnancy: about 300 ml more; breastfeeding: about 700 ml more.
So a 70 kg person who exercises for 30 minutes on a hot day needs about 3.3 litres, or 13 glasses.
It’s not all plain water
Everything you drink counts, and so does water in food. Tea, coffee, milk, buttermilk, lassi, coconut water, soups, dal and juicy fruit like watermelon and oranges all contribute. Sugary drinks add calories, so plain water is still the best main source.
Signs you’re drinking enough
- Your urine is pale yellow.
- You rarely feel very thirsty.
- You don’t get afternoon headaches or tiredness from mild dehydration.
Children, older adults and people working outdoors are most at risk of dehydration in hot weather. Drink small amounts through the day rather than a lot at once.
When to be careful
Drinking many litres in a short time can dilute the salt in your blood, which is dangerous, though rare. People with kidney, heart or liver disease may be told to limit fluids; follow your doctor’s advice over any calculator.
See the bigger picture with the BMI and calorie calculators, and plan rest with the sleep calculator.
Frequently asked questions
How much water should I drink a day?
About 35 ml for each kg of body weight: 2.1 litres at 60 kg, 2.45 litres at 70 kg. Add about 350 ml for every 30 minutes of exercise and 500 ml in hot weather.
Does tea or milk count?
Yes. Tea, milk, buttermilk, soups and juicy fruit all count towards your total. Plain water is still the best choice for most of it.
How do I know I’m drinking enough?
Pale yellow urine and rarely feeling thirsty are good signs. Dark urine, headaches and tiredness can mean you need more.
Can I drink too much water?
It’s rare, but drinking many litres in a short time can be harmful. People with kidney, heart or liver problems may need to limit fluids and should follow their doctor’s advice.