Evidence-based & interactive

Personalized Water Intake Calculator & Hydration Guide

Tailor your daily hydration goal in minutes. Our calculator blends your height, weight, activity level, and climate with research from the National Academies of Sciences, Engineering, and Medicine, the American College of Sports Medicine, and other trusted sources.

Start your calculationExplore hydration tips
Science-backed
Uses guidance from the National Academies, CDC, Harvard, Mayo Clinic, and ACSM.
Dual calculators
Daily intake and pre-activity planning in one streamlined experience.
Privacy-first
All calculations happen in your browser—nothing is stored on our servers.

What you'll find inside

  • • Personalized daily water targets with cups, bottles, and fluid-ounce conversions.
  • • Interactive pacing tools to break your goal into manageable sips.
  • • Guided education on hydration, activity, and climate adjustments.
  • • A pre-activity hydration coach for big workouts or races.
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