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.
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UTI Recovery Water Intake
Extra fluids to flush UTIs.
OpenKidney Stone Prevention Water
2.5-3 L target to prevent stones.
OpenGout Water Intake
Uric-acid flushing hydration.
OpenGERD Water Intake
Reflux-friendly water schedule.
OpenIBS Water Intake
Gut-friendly hydration plan.
OpenPrehypertension Water Intake
Early-stage BP hydration.
OpenThyroid Water Intake
Thyroid-support hydration.
OpenPCOS Water Intake
PCOS-focused daily target.
OpenMigraine Prevention Water Intake
Migraine-avoidance target.
OpenAnxiety Hydration Plan
Calm-support hydration.
OpenDepression Support Water
Mood-support hydration.
OpenInsomnia Water Timing
Sleep-friendly water schedule.
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.