How is daily water intake estimated for adults?
The calculator uses U.S. National Academies Adequate Intake values for total water, then estimates the beverage portion as about 80% of total water.
Health & fitness
Water intake calculator
Estimate total daily water and the beverage portion from U.S. National Academies reference intakes.
- Metric and imperial units
- Instant updates as inputs change
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Daily total water reference2.7 L/day
U.S. reference- Approximate US fluid ounces
- 91 fl oz/day
- Estimated beverages portion
- 2.2 L/day
- Estimated food-water portion
- 0.5 L/day
This is total water from all beverages and food. Heat, altitude, exercise, illness, and medications can change needs.
Calculation notes
Understand the Water intake calculator
Uses U.S. National Academies Adequate Intake values for total water from beverages and food, plus a beverage estimate based on the approximately 80% share.
How much water should an adult woman drink each day?
For an adult woman, the reference is 2.7 L/day total water, with roughly 2.2 L/day estimated from beverages and the rest from food.
Does total water intake include food and other beverages?
- “Total water” includes both drinks and moisture in food.
- Hot weather, altitude, and prolonged exercise can increase needs.
When can personal fluid needs differ from general reference values?
- This is a population reference, not a prescription.
- Heart, kidney, or electrolyte conditions can require individualized fluid limits.
Content and calculation reviewed: