Water Intake Calculator
Estimate your daily water intake from your body weight and exercise, in litres and cups.
How to use it
- Enter your weight Your body weight in kilograms.
- Add exercise time Minutes of exercise on a typical day.
- Read your target Daily water in litres and cups.
Examples
| 70 kg, 30 min | ~2.7 L |
|---|---|
| in cups | ~11 cups |
About this tool
Staying hydrated supports almost everything your body does, but “drink eight glasses” is a blunt rule. This calculator tailors a daily water target to your body weight and how much you exercise, giving the figure in both litres and cups.
It’s a general guideline rather than a strict prescription — hot weather, a salty diet or illness all change your needs, and thirst is a useful signal too. It isn’t medical advice. Everything is computed in your browser.
Frequently asked questions
How is the estimate calculated?
It uses about 33 ml of water per kilogram of body weight, plus an extra allowance for the time you spend exercising.
Is more always better?
No. Needs vary with climate, diet and health, and drinking far more than you need isn't beneficial. Use this as a rough guide.
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Updated June 14, 2026