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 EGFR 75
Fluid target when kidney function is egfr 75.
OpenWater Intake at EGFR 60
Fluid target when kidney function is egfr 60.
OpenWater Intake at EGFR 50
Fluid target when kidney function is egfr 50.
OpenWater Intake at EGFR 45
Fluid target when kidney function is egfr 45.
OpenWater Intake at EGFR 30
Fluid target when kidney function is egfr 30.
OpenWater Intake at EGFR 20
Fluid target when kidney function is egfr 20.
OpenWater Intake at EGFR 15
Fluid target when kidney function is egfr 15.
OpenWater Intake at CKD 2
Fluid target when kidney function is ckd 2.
OpenWater Intake at CKD 3
Fluid target when kidney function is ckd 3.
OpenWater Intake at BP 90/60
Hydration when blood pressure is 90/60.
OpenWater Intake at BP 100/70
Hydration when blood pressure is 100/70.
OpenWater Intake at BP 110/70
Hydration when blood pressure is 110/70.
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.