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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Senior Water Intake at Age 86
Age-adjusted daily hydration target for a 86-year-old senior.
OpenSenior Water Intake at Age 87
Age-adjusted daily hydration target for a 87-year-old senior.
OpenSenior Water Intake at Age 88
Age-adjusted daily hydration target for a 88-year-old senior.
OpenSenior Water Intake at Age 89
Age-adjusted daily hydration target for a 89-year-old senior.
OpenSenior Water Intake at Age 90
Age-adjusted daily hydration target for a 90-year-old senior.
OpenSenior Water Intake at Age 91
Age-adjusted daily hydration target for a 91-year-old senior.
OpenSenior Water Intake at Age 92
Age-adjusted daily hydration target for a 92-year-old senior.
OpenSenior Water Intake at Age 93
Age-adjusted daily hydration target for a 93-year-old senior.
OpenSenior Water Intake at Age 94
Age-adjusted daily hydration target for a 94-year-old senior.
OpenSenior Water Intake at Age 95
Age-adjusted daily hydration target for a 95-year-old senior.
OpenSenior Water Intake at Age 96
Age-adjusted daily hydration target for a 96-year-old senior.
OpenSenior Water Intake at Age 97
Age-adjusted daily hydration target for a 97-year-old senior.
OpenSimple, accurate, personalized
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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.