Water Intake Calculator
Get a rough daily water target from your body weight, today’s exercise and the weather.
Result
Enter your weight and activity.
How to use this calculator
- Enter your weight and minutes of exercise, and tick hot weather if it applies.
Formula
Base = 35 ml per kg of body weight, plus 500 ml per hour of exercise and 500 ml in hot or humid weather.
Worked example
70 kg with 30 minutes of exercise
2,450 ml + 250 ml = 2.7 litres, about 11 glasses.
Assumptions and limitations
- Everything runs in your browser; nothing you enter is uploaded or stored.
- A general guide, not medical advice. People with heart or kidney conditions should follow their doctor’s advice.
Frequently asked questions
Do other drinks count?
Yes — tea, coffee, milk and water in food all contribute.
Can I drink too much?
Yes, very large amounts in a short time can be dangerous. Drink to thirst and spread it through the day.