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 — Malaysia
Localized daily hydration target for malaysia residents with climate factored in.
OpenWater Intake — Singapore
Localized daily hydration target for singapore residents with climate factored in.
OpenWater Intake — Australia
Localized daily hydration target for australia residents with climate factored in.
OpenWater Intake — New Zealand
Localized daily hydration target for new zealand residents with climate factored in.
OpenWater Intake — Usa
Localized daily hydration target for usa residents with climate factored in.
OpenWater Intake — Canada
Localized daily hydration target for canada residents with climate factored in.
OpenWater Intake — Mexico
Localized daily hydration target for mexico residents with climate factored in.
OpenWater Intake — Brazil
Localized daily hydration target for brazil residents with climate factored in.
OpenWater Intake — Argentina
Localized daily hydration target for argentina residents with climate factored in.
OpenWater Intake — Uk
Localized daily hydration target for uk residents with climate factored in.
OpenWater Intake — France
Localized daily hydration target for france residents with climate factored in.
OpenWater Intake — Germany
Localized daily hydration target for germany residents with climate factored in.
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.