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 — High Fiber Diet
Daily fluid target on the high fiber diet.
OpenPost-Knee Surgery Water Intake
Recovery hydration plan after knee surgery.
OpenPost-Hip Surgery Water Intake
Recovery hydration plan after hip surgery.
OpenPost-Shoulder Surgery Water Intake
Recovery hydration plan after shoulder surgery.
OpenPost-Spine Surgery Water Intake
Recovery hydration plan after spine surgery.
OpenPost-Bariatric Surgery Water Intake
Recovery hydration plan after bariatric surgery.
OpenPost-Gallbladder Surgery Water Intake
Recovery hydration plan after gallbladder surgery.
OpenPost-Appendectomy Water Intake
Recovery hydration plan after appendectomy.
OpenPost-C Section Recovery Water Intake
Recovery hydration plan after c section recovery.
OpenPost-Hernia Repair Water Intake
Recovery hydration plan after hernia repair.
OpenPost-Tonsillectomy Water Intake
Recovery hydration plan after tonsillectomy.
OpenPost-Cataract Surgery Water Intake
Recovery hydration plan after cataract surgery.
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.