About the Water Intake Calculator

Daily water intake recommendations are based on your body weight, activity level, and climate — because every person's hydration needs differ. Proper hydration supports kidney function, body temperature regulation, nutrient transport, and cognitive performance. This calculator gives you a personalised daily water target rather than the generic "8 glasses a day" advice.

How to Use

  1. Enter your body weight in kg or lbs
  2. Select your typical daily activity level
  3. Choose your climate (cool, warm, or hot and humid)
  4. Select your preferred output unit, then click Calculate to see your daily water target

Formula Used

Base = Weight (kg) × 33 mL/day

Activity Add-on:
Light: +350 mL | Moderate: +700 mL
Very Active: +1,000 mL | Athlete: +1,500 mL

Climate Add-on:
Warm: +250 mL | Hot & Humid: +500 mL

Total = Base + Activity + Climate

Add an extra 300–500 mL for every 30 minutes of vigorous exercise. Hot climates and illness also increase needs significantly.

Understanding Your Results

Daily Water Need Your total recommended intake in your chosen unit — spread this evenly throughout the day rather than drinking large amounts at once.
Exercise Adjustment The extra fluid added for your activity level and climate. Sweat increases fluid loss significantly — drink before, during, and after exercise.
Minimum Intake Bare minimum for healthy kidney function is approximately 1,500 mL/day (6 glasses). Below this level, kidney stones and urinary tract issues become more likely.

Medical Disclaimer

This calculator provides estimates for general informational purposes only. Results are not a substitute for professional medical advice. Consult a qualified healthcare provider for personalized guidance.