Water Intake Calculator
Daily hydration needs based on weight, activity and climate
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
- Enter your body weight in kg or lbs
- Select your typical daily activity level
- Choose your climate (cool, warm, or hot and humid)
- Select your preferred output unit, then click Calculate to see your daily water target
Formula Used
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
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.