Water Intake Calculator
Estimate how much water you should drink a day based on weight and activity.
"Eight glasses a day" is a catchy rule that ignores the two things that actually matter: your body size and how much you sweat. A larger, active person needs considerably more water than a smaller, sedentary one, and exercise adds a real hydration cost on top of baseline needs.
Enter your weight and how long you exercise, and this calculator estimates your daily water target — using roughly 30–35 ml per kilogram of body weight, plus extra for activity — shown in both liters and cups. It's a personalized starting point far more useful than a one-size-fits-all number. Listen to thirst and urine color to fine-tune.
How to use Water Intake Calculator
- 1
Enter your weight
In kilograms.
- 2
Add your exercise
Minutes of activity on a typical day.
- 3
See your target
Daily water in liters and cups.
Features
- Personalized by body weight
- Adds for exercise time
- Shown in liters and cups
Frequently asked questions
Common mistakes to avoid
- Treating the number as exact — climate, health and diet all shift real needs.
- Front-loading all water at once instead of spreading it through the day.
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