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 120 lb
Precise daily target for a 120 lb adult.
OpenWater Intake for 121 lb
Precise daily target for a 121 lb adult.
OpenWater Intake for 122 lb
Precise daily target for a 122 lb adult.
OpenWater Intake for 123 lb
Precise daily target for a 123 lb adult.
OpenWater Intake for 124 lb
Precise daily target for a 124 lb adult.
OpenWater Intake for 125 lb
Precise daily target for a 125 lb adult.
OpenWater Intake for 126 lb
Precise daily target for a 126 lb adult.
OpenWater Intake for 127 lb
Precise daily target for a 127 lb adult.
OpenWater Intake for 128 lb
Precise daily target for a 128 lb adult.
OpenWater Intake for 129 lb
Precise daily target for a 129 lb adult.
OpenWater Intake for 130 lb
Precise daily target for a 130 lb adult.
OpenWater Intake for 131 lb
Precise daily target for a 131 lb 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.