Water Intake Calculator
Estimate your recommended daily water intake.
Estimated Total Daily Water Intake
This calculator provides a general estimate for informational purposes only. It is not a medical device and does not provide medical advice or diagnosis. Always consult a qualified healthcare professional about your individual health circumstances.
Frequently Asked Questions
How is this calculated?
We use the U.S. National Academies' recommended daily total water intake for adults (about 3.7L for men, 2.7L for women, from all fluids and food combined). This reflects actual clinical guidance rather than a per-bodyweight rule of thumb — the National Academies' expert panel has specifically said no such rule of thumb is well-supported.
How does activity level change the recommendation?
We add a flat allowance on top of the baseline: +500ml for moderate activity, +1000ml for high activity, to account for extra fluid lost through sweat. This is an approximation — actual sweat loss depends on intensity, duration, heat and humidity, so treat it as a starting point rather than an exact figure.
Does this include water from food and other drinks?
Yes — the baseline figures already include an estimate of water from food and other beverages, not just plain drinking water.
Do I need more water in hot weather?
Yes. Heat, humidity and altitude all increase fluid loss through sweat, so you may need more than this estimate suggests in hot conditions or during illness.
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