How to use the Water Intake Calculator
- Enter your weight in kg.
- Enter your average daily exercise in minutes.
- Choose your climate.
- Read your daily target in litres and glasses.
Formula used
One glass = 250 ml. About 20% of daily water comes from food, especially fruit, vegetables, yoghurt and soups.
Worked examples
| Weight | Exercise | Climate | Daily water |
|---|---|---|---|
| 55 kg | 0 min | Mild | 1.9 L (8 glasses) |
| 70 kg | 30 min | Hot | 3.3 L (13 glasses) |
| 90 kg | 60 min | Very hot | 4.6 L (18 glasses) |
Signs you need more water
Dark yellow urine, thirst, headache and tiredness are early signs of dehydration. Pale straw-coloured urine is a good sign. Drink more when fasting, in heatwaves and when you are unwell with fever or diarrhoea. People with kidney or heart conditions may need to limit fluids, so follow your doctor's advice. See also the Calorie Calculator.
Frequently asked questions
How many glasses of water should I drink a day?
Most adults need about 8 to 10 glasses (2 to 2.5 litres) of fluid a day, more in hot weather or when active.
Do tea and coffee count?
Yes. Tea, coffee, milk and other drinks count toward your fluid intake, though water is the best choice.
Can you drink too much water?
Yes, but it is rare. Drinking many litres in a short time can lower blood sodium. Spread drinks through the day.
How much water should I drink in a heatwave?
In 35 to 40°C (95 to 104°F) heat, add at least 0.5 to 1 litre to your normal intake, and more if you work outside.
Is it good to drink water before meals?
A glass before meals can help you feel full and is a simple habit for staying hydrated.
Sources and references
Our team builds and tests every tool by hand, checks each formula against official sources (IRS, HMRC, the Income Tax Department of India, CBSE, NHS, WHO) and reviews pages whenever rules change. Last reviewed on . Spotted a mistake? Tell us.