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Estimate daily water needs from weight, activity and climate — see liters, cups and hourly intake.
Estimate daily water needs from weight, activity and climate — see liters, cups and hourly intake.
Enter values above and click Calculate — results will appear here with the formula explained.
Daily fluid need is approximated from weight, climate and activity sweat losses rather than the generic eight-glasses myth. The baseline multiplies kilos by roughly 33 ml, then adds about 350 ml per 30 minutes of moderate exercise and a climate addend for hot or humid environments; food moisture contributes roughly 20% of the displayed liters, so explicit drinking volume is slightly less. At 70 kg temperate and sedentary, the baseline sits near 2.3 liters, rising toward 3.0 liters with 45 minutes of daily exercise in warm weather.
Let thirst and pale-yellow urine be the ultimate referee — no formula beats hourly feedback from concentration and frequency. Spread intake through the day rather than loading it at once; extreme rapid intake can dilute serum sodium into hyponatremia, a rare but real risk the calculator's conservative ceilings are designed to avoid.
Estimate daily water needs from weight, activity and climate — see liters, cups and hourly intake. Formula: Base = weight*0.033 L. Example: At 70kg, moderate activity, temperate: base 2.31L, plus ~0.35L = ~2.7L total, about 11 cups, ~0.17L per hour.
Daily fluid need is approximated from weight, climate and activity sweat losses rather than the generic eight-glasses myth. The baseline multiplies kilos by roughly 33 ml, then adds about 350 ml per 30 minutes of moderate exercise and a climate addend for hot or humid environments; food moisture contributes roughly 20% of the displayed liters, so explicit drinking volume is slightly less. At 70 kg temperate and sedentary, the baseline sits near 2.3 liters, rising toward 3.0 liters with 45 minutes of daily exercise in warm weather.
Let thirst and pale-yellow urine be the ultimate referee — no formula beats hourly feedback from concentration and frequency. Spread intake through the day rather than loading it at once; extreme rapid intake can dilute serum sodium into hyponatremia, a rare but real risk the calculator's conservative ceilings are designed to avoid.
At 70kg, moderate activity, temperate: base 2.31L, plus ~0.35L = ~2.7L total, about 11 cups, ~0.17L per hour.
Formulas are standard public references (see our methodology). External standards are cited in the text where they apply.
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