About
About WaterIntakeCalculator
A single, focused resource for daily water intake — across life stages, activity levels, and species.
Our Mission
Hydration advice online is fragmented, contradictory, and often wrong. WaterIntakeCalculator exists to fix that. We built one trustworthy place where anyone — a parent, an athlete, a farmer, a pet owner, or a gardener — can get a fast, science-backed answer to "how much water do I (or they) need today?"
Every calculator on this site is grounded in published guidelines from bodies like the World Health Organization, the U.S. Institute of Medicine, the National Research Council (for animals), and reviewed veterinary literature. We show the formula, cite the source, and note where individual variation matters.
What We Stand For
Evidence-Based
Every formula is sourced from published guidelines: WHO, IOM, NRC, AAFCO, and peer-reviewed research.
Transparent
We show our math. Each calculator explains the formula, assumptions, and limitations openly.
Inclusive
Tools for every life stage and species — infants, athletes, pregnant mothers, seniors, dogs, cats, livestock, plants.
Free & Ad-Light
No paywalls, no forced signups. Just fast, accurate hydration tools that work on any device.
Our Methodology
Each calculator starts as a formula from a primary source — a WHO recommendation, an IOM Adequate Intake figure, or an NRC animal nutrition table. We adapt it into a clear input/output tool, document the assumptions, and add adjustments for factors that meaningfully change the answer: body weight, activity, climate, pregnancy, lactation, life stage, or ambient temperature.
Every page includes a "How it works" section so you can see exactly how your result was calculated. When the science is uncertain or individualization matters, we say so. When a result should be confirmed with a doctor, dietitian, or veterinarian, we say that too.
Important Limits
Our results are general estimates. Individual water needs vary with medical conditions, medications, climate, activity, and factors no general calculator can fully capture. If you are pregnant, managing a health condition, or caring for a sick animal, please seek personalized professional advice.