Water Intake Calculator - Daily Hydration

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Find out how much water you should drink each day with our Water Intake Calculator. It uses the standard weight-based guideline — about 33 ml per kg of body weight — plus extra fluid for exercise, and shows the result in liters, cups, and US fluid ounces.

Hydration needs vary with body size, activity, and climate. A 70 kg person with no exercise needs about 2.3 L daily; each 30 minutes of exercise adds roughly 0.35 L to replace sweat losses. Hot weather and high-altitude conditions push needs higher still.

All beverages count toward the total — coffee and tea included — and food contributes another 20% of daily fluid. Spread your intake across the day rather than drinking large amounts at once, and use thirst plus urine color as real-time signals. The calculator gives you a daily target; your body gives you the fine-tuning.

Formule
Water (L) = weight (kg) × 0.033 + exercise (min) ÷ 30 × 0.35

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How much water should I drink per day?
A common guideline is 30-35 ml per kg of body weight, plus extra for exercise (about 0.35 L per 30 minutes). A 70 kg person with no exercise needs roughly 2.3 L per day.
Does exercise increase water needs?
Yes. You lose 0.5-2 L of fluid per hour of sweating. The calculator adds about 0.35 L for every 30 minutes of exercise — drink before, during, and after workouts.
Do coffee and tea count?
Yes. Despite folklore, moderate caffeine does not dehydrate you — coffee, tea, milk, and juice all contribute to hydration. Food provides another ~20% of daily fluid.
Can I drink too much water?
Rarely, but yes — hyponatremia occurs when extreme intake dilutes blood sodium. Spread intake through the day and drink to thirst rather than forcing liters at once.

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