What this calculator does
This water intake calculator gives a practical daily fluid estimate based on weight and activity. It is a planning guide, not a medical target.
Formula used
The calculator starts with 35 ml per kilogram of body weight, adds fluid for exercise time and adds an allowance for warm conditions or heavy sweating.
How to read the result
Fluid needs vary with food, climate, sweat rate, pregnancy, illness and medication. Thirst, urine colour and medical advice matter more than a single formula.
Assumptions
- For generally healthy adults.
- Includes fluid from drinks, not just plain water.
- Does not apply to medical fluid restrictions.
Sources and checks
Source links are included so you can check important formulas, thresholds and assumptions.
Frequently asked questions
Does food count toward water intake?
Yes. Total water intake includes water from drinks and food, though this calculator focuses on a drinkable daily target.