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💧 Water Intake Calculator
Work out how much water you should drink each day from your body weight and activity level — in litres and glasses.
About this Water Intake Calculator
Water Intake Calculator estimates your daily fluid needs from the widely used guide of about 33 ml of water per kilogram of body weight, plus extra for physical activity, which increases losses through sweat. The result is shown in litres and in familiar 250 ml glasses so it is easy to follow.
How to use it
- Enter your body weight in kilograms.
- Choose the activity level that matches a typical day.
- Press Calculate water intake.
- Aim for the litres shown, spread across the day rather than all at once.
Example
A 70 kg person with a moderate activity level needs about 2.81 litres a day — around 11 glasses.
Frequently asked questions
Does tea, coffee and food count?
Yes, all fluids and watery foods contribute, but plain water should make up most of your intake.
Should I drink more in summer?
Yes. Heat, humidity and illness all raise your needs — the calculator result is a fair-weather baseline.
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