Water Intake Calculator
Estimate how much water to drink each day for your weight and activity.
Daily water
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In cups (250 ml)
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Results update as you type.
About this calculator
This calculator estimates a daily water target from your body weight and activity level. It is a general guideline — climate, health and diet also matter, and much of your fluid also comes from food.
Frequently asked questions
How much water should I drink a day?
A common guideline is about 30-35 ml per kilogram of body weight, plus extra for exercise. This calculator adds roughly 350 ml per 30 minutes of activity.
Does other drink and food count?
Yes. Food provides around 20% of daily fluid, and all drinks count toward hydration. Treat the number as a total fluid guide, not water alone.
Results are estimates for general guidance only, not financial, medical or tax advice.