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 — Doctor Shift
Job-specific hydration for doctor shift — shift length, heat exposure, and workload adjustments.
OpenWater Intake — Construction Worker
Job-specific hydration for construction worker — shift length, heat exposure, and workload adjustments.
OpenWater Intake — Warehouse Worker
Job-specific hydration for warehouse worker — shift length, heat exposure, and workload adjustments.
OpenWater Intake — Factory Worker
Job-specific hydration for factory worker — shift length, heat exposure, and workload adjustments.
OpenWater Intake — Delivery Driver
Job-specific hydration for delivery driver — shift length, heat exposure, and workload adjustments.
OpenWater Intake — Truck Driver
Job-specific hydration for truck driver — shift length, heat exposure, and workload adjustments.
OpenWater Intake — Taxi Driver
Job-specific hydration for taxi driver — shift length, heat exposure, and workload adjustments.
OpenWater Intake — Teacher Classroom
Job-specific hydration for teacher classroom — shift length, heat exposure, and workload adjustments.
OpenWater Intake — Office Worker
Job-specific hydration for office worker — shift length, heat exposure, and workload adjustments.
OpenWater Intake — Call Center
Job-specific hydration for call center — shift length, heat exposure, and workload adjustments.
OpenWater Intake — Retail Worker
Job-specific hydration for retail worker — shift length, heat exposure, and workload adjustments.
OpenWater Intake — Chef Kitchen
Job-specific hydration for chef kitchen — shift length, heat exposure, and workload adjustments.
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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.