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 a Truck Driver
Shift-adjusted daily target for a truck driver.
OpenWater Intake for a Construction Worker
Shift-adjusted daily target for a construction worker.
OpenWater Intake for a Roofer
Shift-adjusted daily target for a roofer.
OpenWater Intake for a Welder
Shift-adjusted daily target for a welder.
OpenWater Intake for a Miner
Shift-adjusted daily target for a miner.
OpenWater Intake for a Chef
Shift-adjusted daily target for a chef.
OpenWater Intake for a Barista
Shift-adjusted daily target for a barista.
OpenWater Intake for a Teacher
Shift-adjusted daily target for a teacher.
OpenWater Intake for a Student
Shift-adjusted daily target for a student.
OpenWater Intake for a Lawyer
Shift-adjusted daily target for a lawyer.
OpenWater Intake for a Software Engineer
Shift-adjusted daily target for a software engineer.
OpenWater Intake for a Designer
Shift-adjusted daily target for a designer.
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.