Scientific Water Intake Calculator

Male
Female
Sedentary
Little or no exercise
Lightly Active
Light exercise 1-3 days/week
Moderately Active
Moderate exercise 3-5 days/week
Very Active
Hard exercise 6-7 days/week
Extremely Active
Very hard exercise & physical job
Pregnancy
Breastfeeding
High Altitude
Fever/Illness

Your Personalized Water Intake

0
liters per day

Detailed Recommendations

Scientific Hydration Guidance

  • Timing Matters: Drink 500ml upon waking to combat overnight dehydration
  • Exercise Hydration: 500ml 2h before exercise + 150-350ml every 15-20min during
  • Urine Color: Aim for pale yellow (1-3 on urine color chart)
  • Electrolytes: Include sodium (500-700mg/L) for exercise >1h or heavy sweating
  • Overhydration Risk: Don't exceed 1.4L/h to avoid hyponatremia
Based on recommendations from the European Food Safety Authority (EFSA), Institute of Medicine (IOM), and American College of Sports Medicine (ACSM).

Scientific Basis of This Calculator

This scientifically-validated water intake calculator uses multiple physiological factors to provide personalized hydration recommendations.

Key Scientific Improvements:

  • Body Surface Area (BSA) Calculation: Incorporates height and weight using the Mosteller formula for more accurate needs estimation
  • Age-Adjusted Calculations: Accounts for reduced thirst perception in elderly (≥65 years)
  • Pregnancy/Breastfeeding: Adds 300ml/day for pregnancy and 700ml/day for breastfeeding (EFSA guidelines)
  • High Altitude Adjustment: +400ml/day at >2500m due to increased respiratory water loss
  • Illness Adjustment: +500ml/day per °C above 37°C body temperature
  • Climate Factors: Based on WHO heat stress hydration guidelines

Calculation Methodology:

The calculator uses the following formula for base water needs:
Total Water = (Basal Metabolic Water + Activity Water + Climate Adjustment) × Individual Factors

Note: This calculator provides recommendations for healthy adults. Medical conditions (kidney disease, heart failure, etc.) require physician consultation.

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