Proper hydration affects energy, cognition, metabolism, and athletic performance.
Base: 35ml per kg of body weight. Add 500–1000ml per hour of exercise. Add 500ml in hot weather.
This tool is most useful for tracking trends rather than obsessing over a single data point. Run the calculation monthly with consistent measurement conditions to see whether your metric is moving in the right direction.
Many users apply adult health classifications to children and teenagers, which is incorrect. Paediatric norms for height, weight, BMI, and body composition are age-and-sex-specific. Use age-appropriate reference tools for anyone under 18.
A nurse calculates a patient's health metric during a routine assessment, then uses the result alongside other clinical indicators to contextualise the finding — correctly treating the number as one data point among several rather than a standalone answer.
~35ml per kg of body weight, plus extra for exercise and heat. A 70kg person needs ~2.5L base.
CalcPlanet – Free Online Calculators
725+ free calculators and 108 tools for math, money, health, and everyday life. Instant results, verified formulas, no sign-up.
By CalcPlanet Editorial · Reviewed against our Editorial Standards and Formula Sources.
CalcPlanet calculators are free, privacy-first, and formula-reviewed.
Editorial Standards · Formula Sources · Privacy · Terms · Contact
