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 Journalist
Shift-adjusted daily target for a journalist.
OpenWater Intake for a Musician
Shift-adjusted daily target for a musician.
OpenWater Intake for a Farmer
Shift-adjusted daily target for a farmer.
OpenWater Intake for a Gardener
Shift-adjusted daily target for a gardener.
OpenWater Intake for a Electrician
Shift-adjusted daily target for a electrician.
OpenWater Intake for a Plumber
Shift-adjusted daily target for a plumber.
OpenWater Intake for a Hvac Technician
Shift-adjusted daily target for a hvac technician.
OpenWater Intake for a Mechanic
Shift-adjusted daily target for a mechanic.
OpenWater Intake for a Warehouse Worker
Shift-adjusted daily target for a warehouse worker.
OpenWater Intake for a Factory Worker
Shift-adjusted daily target for a factory worker.
OpenWater Intake for a Flight Attendant
Shift-adjusted daily target for a flight attendant.
OpenWater Intake for a Delivery Rider
Shift-adjusted daily target for a delivery rider.
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.