About Water Intake Calculator

Our Mission

Water Intake Calculator provides accurate, evidence-based daily hydration recommendations to help people achieve better health outcomes. Every calculation is based on peer-reviewed science from the National Academies of Sciences, Engineering, and Medicine.

The Formula

Water Intake Calculator uses the NASEM 2004 Dietary Reference Intakes formula as its foundation. This standard sets Adequate Intake at 3.7 liters per day for men and 2.7 liters per day for women based on observed intake levels of healthy, well-hydrated adults in United States population studies.

The base calculation starts at 0.5 fluid ounces per pound of body weight per day. Water Intake Calculator then applies adjustments for physical activity based on ACSM Exercise and Fluid Replacement guidelines, and for climate based on Mayo Clinic Hydration protocols.

Evidence Sources

• National Academies of Sciences, Engineering, and Medicine. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. Washington DC: National Academies Press, 2004.
• American College of Sports Medicine. Exercise and Fluid Replacement. Medicine and Science in Sports and Exercise, 2007.
• Mayo Clinic. Water: How much should you drink every day? Mayo Foundation for Medical Education and Research, 2022.

Privacy

Water Intake Calculator runs entirely in your browser. No personal data is collected, stored, or transmitted. No account is required. Your health information never leaves your device.

Contact

Water Intake Calculator LLC, United States
Email: support@waterintakecalculator.org