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 78 kg
Precise daily target for a 78 kg adult.
OpenWater Intake for 79 kg
Precise daily target for a 79 kg adult.
OpenWater Intake for 80 kg
Precise daily target for a 80 kg adult.
OpenWater Intake for 81 kg
Precise daily target for a 81 kg adult.
OpenWater Intake for 82 kg
Precise daily target for a 82 kg adult.
OpenWater Intake for 83 kg
Precise daily target for a 83 kg adult.
OpenWater Intake for 84 kg
Precise daily target for a 84 kg adult.
OpenWater Intake for 85 kg
Precise daily target for a 85 kg adult.
OpenWater Intake for 86 kg
Precise daily target for a 86 kg adult.
OpenWater Intake for 87 kg
Precise daily target for a 87 kg adult.
OpenWater Intake for 88 kg
Precise daily target for a 88 kg adult.
OpenWater Intake for 89 kg
Precise daily target for a 89 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.