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 42% Body Fat
Hydration target for 42% body fat based on lean mass.
OpenWater Intake at 45% Body Fat
Hydration target for 45% body fat based on lean mass.
OpenWater Intake at 48% Body Fat
Hydration target for 48% body fat based on lean mass.
OpenWater Intake at 50% Body Fat
Hydration target for 50% body fat based on lean mass.
OpenWater Intake — High Sodium
Fluid target when lab shows high sodium.
OpenWater Intake — Low Sodium
Fluid target when lab shows low sodium.
OpenWater Intake — High Potassium
Fluid target when lab shows high potassium.
OpenWater Intake — Low Potassium
Fluid target when lab shows low potassium.
OpenWater Intake — High Creatinine
Fluid target when lab shows high creatinine.
OpenWater Intake — Low Egfr
Fluid target when lab shows low egfr.
OpenWater Intake — High Bun
Fluid target when lab shows high bun.
OpenWater Intake — High Hematocrit
Fluid target when lab shows high hematocrit.
OpenSimple, accurate, personalized
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Choose the one that matches your situation from the grid above.
Enter a few details
Weight, activity, climate, species — takes under 30 seconds.
Get your target
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.