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
Crohn's Disease Water Intake
IBD daily target.
OpenUlcerative Colitis Water
UC daily hydration.
OpenCeliac Disease Water
Celiac recovery hydration.
OpenLupus Water Intake
Autoimmune hydration plan.
OpenMultiple Sclerosis Water
MS hydration plan.
OpenFibromyalgia Water Intake
Widespread-pain hydration.
OpenChronic Fatigue Water Intake
CFS/ME hydration.
OpenCancer Recovery Water Intake
Treatment recovery hydration.
OpenChemotherapy Water Intake
Chemo-day hydration.
OpenDialysis Patient Water Guide
Dialysis fluid limits.
OpenChronic Kidney Disease Water
CKD hydration plan.
OpenHeart Failure Water Limit
CHF fluid-restriction plan.
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.