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 74
Age-adjusted daily hydration target for a 74-year-old senior.
OpenSenior Water Intake at Age 75
Age-adjusted daily hydration target for a 75-year-old senior.
OpenSenior Water Intake at Age 76
Age-adjusted daily hydration target for a 76-year-old senior.
OpenSenior Water Intake at Age 77
Age-adjusted daily hydration target for a 77-year-old senior.
OpenSenior Water Intake at Age 78
Age-adjusted daily hydration target for a 78-year-old senior.
OpenSenior Water Intake at Age 79
Age-adjusted daily hydration target for a 79-year-old senior.
OpenSenior Water Intake at Age 80
Age-adjusted daily hydration target for a 80-year-old senior.
OpenSenior Water Intake at Age 81
Age-adjusted daily hydration target for a 81-year-old senior.
OpenSenior Water Intake at Age 82
Age-adjusted daily hydration target for a 82-year-old senior.
OpenSenior Water Intake at Age 83
Age-adjusted daily hydration target for a 83-year-old senior.
OpenSenior Water Intake at Age 84
Age-adjusted daily hydration target for a 84-year-old senior.
OpenSenior Water Intake at Age 85
Age-adjusted daily hydration target for a 85-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.