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 for 138 kg
Precise daily target for a 138 kg adult.
OpenWater Intake for 139 kg
Precise daily target for a 139 kg adult.
OpenWater Intake for 140 kg
Precise daily target for a 140 kg adult.
OpenWater Intake for 141 kg
Precise daily target for a 141 kg adult.
OpenWater Intake for 142 kg
Precise daily target for a 142 kg adult.
OpenWater Intake for 143 kg
Precise daily target for a 143 kg adult.
OpenWater Intake for 144 kg
Precise daily target for a 144 kg adult.
OpenWater Intake for 145 kg
Precise daily target for a 145 kg adult.
OpenWater Intake for 146 kg
Precise daily target for a 146 kg adult.
OpenWater Intake for 147 kg
Precise daily target for a 147 kg adult.
OpenWater Intake for 148 kg
Precise daily target for a 148 kg adult.
OpenWater Intake for 149 kg
Precise daily target for a 149 kg adult.
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.