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 on Antibiotic
Daily fluid target when taking antibiotic — side-effect adjusted.
OpenWater Intake on Chemotherapy
Daily fluid target when taking chemotherapy — side-effect adjusted.
OpenWater Intake on Dialysis
Daily fluid target when taking dialysis — side-effect adjusted.
OpenWater Intake on Cpap
Daily fluid target when taking cpap — side-effect adjusted.
OpenWater Intake on Albuterol
Daily fluid target when taking albuterol — side-effect adjusted.
OpenWater Intake on Ppi
Daily fluid target when taking ppi — side-effect adjusted.
OpenWater Intake on Beta Blocker
Daily fluid target when taking beta blocker — side-effect adjusted.
OpenWater Intake on Ace Inhibitor
Daily fluid target when taking ace inhibitor — side-effect adjusted.
OpenWater Intake on Glp1
Daily fluid target when taking glp1 — side-effect adjusted.
OpenHow Many 8 oz Bottles Per Day?
Number of 8 oz bottles you need daily to hit your hydration target.
OpenHow Many 12 oz Bottles Per Day?
Number of 12 oz bottles you need daily to hit your hydration target.
OpenHow Many 16 oz Bottles Per Day?
Number of 16 oz bottles you need daily to hit your hydration target.
OpenSimple, accurate, personalized
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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.