Estimate a daily water target from your body weight, exercise and climate, in millilitres, litres, cups and ounces.
How the water intake calculator works
Hydration needs scale with body size, activity and heat rather than following one fixed number for everyone. This calculator starts from roughly 33 mL per kilogram of body weight and adds for exercise and climate.
About a fifth of typical fluid intake comes from food, so the drinking target is lower than the total requirement — the calculator shows both.
Step by step
- Enter your body weight.
- Add daily exercise minutes and your climate.
- Adjust for pregnancy or breastfeeding if relevant.
Formula reference
base = weight in kg × 33 mL
+ 350 mL per 30 minutes of exercise · × climate factor
Try it with these numbers
The calculator opens with a pregnant or breastfeeding of No. On those figures the daily water target is 2,660 mL. Underneath, In litres comes out at 2.66 L and In US cups at 11.2 cups. Change any field and every figure updates as you type.
Frequently asked questions
Is eight glasses a day correct?
It is a rough approximation that ignores body size and activity. A weight-based figure is more useful.
Can you drink too much water?
Yes — excessive intake in a short period can dilute blood sodium dangerously. Spread intake through the day.
Do tea and coffee count?
Yes. The mild diuretic effect of caffeine does not offset the fluid, so they contribute to your total.