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
Student Water Intake
Study-day hydration target.
OpenDriver Water Intake
Long-drive hydration plan.
OpenNurse 12-Hour Shift Water
Nursing shift hydration plan.
OpenDoctor Shift Water Intake
On-call hydration target.
OpenTeacher Water Intake
Classroom hydration schedule.
OpenConstruction Worker Hydration
Heavy-work outdoor target.
OpenUnderground Miner Water Intake
Hot-environment hydration.
OpenChef Kitchen Water Intake
Hot-kitchen daily target.
OpenDelivery Rider Hydration
On-the-move hydration.
OpenPilot Water Intake
Cockpit + long-haul flight hydration.
OpenCabin Crew Water Intake
Flight-attendant hydration.
OpenGamer / Esports Water Intake
Long-session gaming hydration.
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.