Human Calculators
Daily water intake calculators for adults — men, women, elderly, weight-based, and weather-based.
Most popular in Human Calculators
Adult Daily Water Intake
Personalized daily water target for healthy adults, adjusted for weight, activity, and climate.
Open calculatorElderly Water Intake (65+)
Daily hydration target for older adults, with a safe minimum floor and climate adjustments.
Open calculatorWater Intake for Weight Loss
Higher-end daily target with pre-meal water boost that supports satiety and weight loss.
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Water Intake at Age 78
Daily hydration target for a 78-year-old adult.
OpenWater Intake at Age 79
Daily hydration target for a 79-year-old adult.
OpenWater Intake at Age 80
Daily hydration target for a 80-year-old adult.
OpenWater Intake in Portugal
Climate-adjusted daily water target for adults in Portugal.
OpenWater Intake in Denmark
Climate-adjusted daily water target for adults in Denmark.
OpenWater Intake in Finland
Climate-adjusted daily water target for adults in Finland.
OpenWater Intake in Poland
Climate-adjusted daily water target for adults in Poland.
OpenWater Intake in Russia
Climate-adjusted daily water target for adults in Russia.
OpenWater Intake in Greece
Climate-adjusted daily water target for adults in Greece.
OpenWater Intake in Sri Lanka
Climate-adjusted daily water target for adults in Sri Lanka.
OpenWater Intake in Nepal
Climate-adjusted daily water target for adults in Nepal.
OpenWater Intake for Height 141 cm
Daily hydration target for a 141 cm tall adult.
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Choose the one that matches your situation from the grid above.
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Weight, activity, climate, species — takes under 30 seconds.
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A research-backed daily target plus an hourly schedule.
Learn the science behind human calculators
Read our in-depth guides for research-backed context on every calculator here.