Water Intake Calculator
Estimate how much water you should drink per day based on body weight and exercise.
About this tool
Daily fluid needs scale primarily with body size and activity. A widely used estimate is around 33 milliliters per kilogram of body weight per day, plus roughly 350 milliliters for every 30 minutes of exercise to replace sweat losses. This calculator applies that method and reports the total in liters, milliliters, and US cups.
The figure covers all fluids, not just plain water: tea, coffee, milk, and the water content of food all count toward it. Thirst, urine color, and climate are better day to day guides than any fixed number; treat the result as a baseline, and drink more in heat or during illness.
Frequently asked questions
Is the 8 glasses a day rule true?
It is a rough simplification. Needs vary with body size, activity, and climate. Eight 250 ml glasses is 2 liters, which sits inside the typical adult range but is not universal.
Can you drink too much water?
Yes, though it is rare. Drinking many liters in a short period can dilute blood sodium. Spreading intake across the day is the sensible pattern.