About Water Intake Calculator

What We Do

Water Intake Calculator provides free, interactive tools that estimate personal daily water needs based on body weight, age, sex, activity level, and specific life circumstances — including pregnancy, breastfeeding, athletic training, and pet ownership. Every calculator on this site is built around published reference values from recognised public-health and scientific bodies rather than arbitrary rules of thumb.

Our Sources

Baseline recommendations on this site draw on the U.S. National Academies of Sciences, Engineering, and Medicine (NASEM/IOM) Dietary Reference Intakes for the homepage calculator, and on the European Food Safety Authority (EFSA) and World Health Organization (WHO) guidance for our international language pages, each adapted to the relevant national or regional health authority where local guidance exists (for example ICMR-NIN for our Hindi-language page, or FNRI-DOST for our Filipino-language page). Specialty calculators — for pregnancy, breastfeeding, athletes, children, and pets — additionally reference guidance from the American College of Obstetricians and Gynecologists (ACOG), the American College of Sports Medicine (ACSM), the International Society of Sports Nutrition (ISSN), the American Academy of Pediatrics (AAP), and the American Veterinary Medical Association (AVMA). Specific citations appear in the "How This Is Calculated" section of each calculator page.

How Our Calculators Work

Each calculator applies a body-weight-based formula (typically 30–45 mL of water per kilogram of body weight per day, depending on the calculator's purpose), adjusted by activity level, age, and — where relevant — a condition-specific modifier such as pregnancy trimester, training phase, or pet diet type. Results are estimates intended for general wellness purposes. They are not a substitute for individualised medical, veterinary, or sports-nutrition advice, and we say so clearly on every calculator page.

Editorial Standards

Content on this site is written and maintained by the Water Intake Calculator editorial team, with formulas and reference values cross-checked against the primary source documents linked from each calculator page whenever possible. We revise pages when we identify outdated figures or when a cited authority updates its guidance. If you believe any figure on this site is inaccurate or out of date, please contact us — we take factual accuracy seriously, particularly given the health-related nature of this content.

Not Medical Advice

This website and its calculators are provided for general informational and educational purposes only. They do not constitute medical, veterinary, dietary, or sports-nutrition advice, and are not a substitute for consultation with a qualified physician, midwife, registered dietitian, veterinarian, or other qualified professional. Individual hydration needs vary based on health conditions, medications, climate, and other factors a calculator cannot account for. If you have a medical condition, are pregnant or breastfeeding, or have concerns about your or your pet's hydration status, please consult an appropriate healthcare professional.

Our Global Reach

Water Intake Calculator is available in English plus 42 additional languages, each with locale-appropriate health-authority standards, units of measurement, and terminology — not machine-translated interface text alone, but recommendations grounded in the health guidance most relevant to that audience. See the language switcher in the site menu for the full list.