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.
Open calculatorExplore the full library
Water Intake at Age 54
Daily hydration target for a 54-year-old adult.
OpenWater Intake at Age 55
Daily hydration target for a 55-year-old adult.
OpenWater Intake at Age 56
Daily hydration target for a 56-year-old adult.
OpenWater Intake at Age 57
Daily hydration target for a 57-year-old adult.
OpenWater Intake at Age 58
Daily hydration target for a 58-year-old adult.
OpenWater Intake at Age 59
Daily hydration target for a 59-year-old adult.
OpenWater Intake at Age 60
Daily hydration target for a 60-year-old adult.
OpenWater Intake at Age 61
Daily hydration target for a 61-year-old adult.
OpenWater Intake at Age 62
Daily hydration target for a 62-year-old adult.
OpenWater Intake at Age 63
Daily hydration target for a 63-year-old adult.
OpenWater Intake at Age 64
Daily hydration target for a 64-year-old adult.
OpenWater Intake at Age 65
Daily hydration target for a 65-year-old 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.