70 kg with an hour of exercise
70 × 0.033 = 2.31 L, plus 0.5 L for exercise = 2.81 L a day — about 11 glasses of 250 mL.
Water Intake Calculator
Estimate how much water to drink a day from your weight, exercise and the weather.
Result
Enter your values and select Calculate to see the result.
Result
Enter your values and select Calculate to see the result.
Runs in your browser — nothing you enter is sent to a server.
How the Water Intake Calculator works
A common rule of thumb is 30–35 mL of water per kilogram of body weight a day. This calculator uses 33 mL per kg, adds about 0.5 L for every hour of exercise, and adds 10% for hot or humid weather.
For comparison, the US National Academies suggest a total water intake of about 3.7 L a day for men and 2.7 L for women, including the roughly 20% that comes from food.
Formula
litres = (weight kg × 0.033 + exercise hours × 0.5) × 1.1 if hot
Examples
The same day in hot weather
2.81 L × 1.1 = about 3.09 L.
Frequently asked questions
Do coffee and tea count?
Yes. Moderate amounts of tea and coffee hydrate you; so do milk, soup and water-rich foods such as fruit.
How do I know I'm drinking enough?
Pale yellow urine and rarely feeling thirsty are good signs. Thirst, dark urine or headaches can mean you need more.
Can you drink too much water?
Yes — very large amounts in a short time can dangerously lower blood sodium. Some heart and kidney conditions also require limiting fluids, so follow your doctor's advice.
Information:
Good to know
For general information only — not medical advice, diagnosis or treatment. Talk to a doctor or other qualified professional about your health.
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