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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Constipation Relief Water Intake
Water plus fiber protocol for regularity.
OpenHypertension Water Intake
BP-safe hydration target.
OpenPre-diabetic Water Intake
Glucose-stabilizing hydration plan.
OpenType 1 Diabetes Water Intake
Insulin-user hydration target.
OpenType 2 Diabetes Water Intake
Type 2 diabetes daily fluid target.
OpenMen's Daily Water Intake
Daily water target for adult men.
OpenWomen's Daily Water Intake
Daily water target for adult women.
OpenWater Intake for Tall People
Adjusted target for taller adults.
OpenWater Intake for Shorter Adults
Adjusted target for shorter adults.
OpenWater Intake for Overweight Adults
Extra fluids for higher body mass.
OpenWater Intake for Underweight Adults
Fluid target for lower body mass.
OpenDesk Job Hydration
Office worker daily target.
OpenSimple, accurate, personalized
Pick your calculator
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.