Starts at ~35 ml per kg body weight plus activity adjustments.
Water Intake Calculator
Estimate daily water intake based on weight, exercise, and environment.
Science-based
Instant results
100% free
No signup · private
Daily water target
3.0 L
Moderate · Normal climate
From beverages; food also contributes fluid
12
Cups (240 ml)
100
US fl oz
6
Bottles (500 ml)
2,450
Base ml
500
Extra ml
2,950
Total ml
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This tool provides general informational estimates only and is not medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional.
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Frequently asked questions
Clear answers based on established nutrition science.
How much water per day?
A practical starting point is 30–35 ml per kg of body weight, plus extra for exercise and hot or humid weather. Official totals vary — see U.S. National Academies and EFSA hydration guidance.
Sources & methodology
Formulas and reference ranges from peer-reviewed and official sources:
- U.S. National Academies. Hydration guidance (~2.7 L women / 3.7 L men total fluid).
- EFSA. Adequate water intake recommendations.