Quick answer
How much water should I drink per day?
A good daily water intake is about 35 ml per kg of body weight, plus about 500 ml for every 30 minutes of exercise and more in hot weather. For a 70 kg adult with 30 minutes of exercise, that’s about 3 litres, or 12 glasses of 250 ml.
- Rule of thumb: 35 ml × body weight in kg
- Exercise: add about 500 ml per 30 minutes
- Total water (food + drinks): 3.7 L men · 2.7 L women (US National Academies)
How is your daily water intake calculated?
The water intake calculator starts with your body weight, then adds water for exercise and for hot weather. A bigger body needs more water, and sweat losses come on top.
Take a 70 kg adult who exercises for 30 minutes a day. The base is 70 × 35 ml = 2.45 litres. Exercise adds 0.5 litres, giving about 3 litres, or 12 glasses of 250 ml. On a hot day, that rises to about 3.5 litres, or 14 glasses.
How much water a day for your weight?
These figures come straight from the calculator. Glasses are 250 ml, rounded to the nearest whole glass.
| Weight and day | Litres | Glasses |
|---|---|---|
| 50 kg, no exercise | 1.8 L | 7 |
| 60 kg, no exercise | 2.1 L | 8 |
| 60 kg, no exercise, hot weather | 2.6 L | 10 |
| 70 kg, 30 minutes of exercise | 3.0 L | 12 |
| 80 kg, 60 minutes of exercise, hot weather | 4.3 L | 17 |
Indian summers, long commutes on a two-wheeler and outdoor work can push your needs above these numbers. If you think in US fluid ounces, 1 litre is about 33.8 fl oz, so 3 litres is about 101 fl oz.
How can I increase my water intake?
- Keep a 1-litre bottle with you and refill it two or three times
- Drink a glass with every meal and after waking up
- Eat water-rich foods: cucumber, watermelon, oranges, curd
- Add lemon, mint or cucumber if plain water feels boring
Frequently asked questions
How much water should I drink a day?
A common guide is about 35 ml of water per kg of body weight, plus about 500 ml for every 30 minutes of exercise. A 70 kg person who exercises for 30 minutes needs roughly 3 litres a day, or about 12 glasses.
Is 8 glasses of water a day enough?
Eight glasses (about 2 litres) is a reasonable minimum for many adults, but needs vary with body size, activity and climate. The US National Academies suggest total water of about 3.7 litres for men and 2.7 litres for women a day, including water from food.
Does tea or coffee count towards water intake?
Yes. Tea, coffee, milk, buttermilk and water-rich foods like fruit and dal all count. Plain water is still the best everyday choice.
How do I know if I’m drinking enough water?
Pale yellow urine and rarely feeling thirsty are good signs. Dark urine, headaches and tiredness can mean you need more.
How many litres is 12 glasses of water?
Twelve glasses of 250 ml make 3 litres. The calculator shows your daily amount both in litres and as 250 ml glasses.
Can you drink too much water?
Yes, though it’s rare in healthy adults. Drinking several litres in a short time can lower blood sodium, which is dangerous. People with heart or kidney conditions may be told to limit fluids, so follow your doctor’s advice.