GlenCalc

Water intake calculator

The National Academies set an adequate total water intake (from all drinks and food) of about 3.7 L a day for men and 2.7 L for women. About 80% usually comes from drinks.

Your answer

From drinks3.4 LAbout 14 cups
Total water (drinks and food)4.3 L
Drinks in fluid ounces115 fl oz
  • Thirst and pale urine are good everyday guides. People with heart or kidney conditions may be told to limit fluids.

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How we worked it out

Updated as you change the numbers.

  1. Base adequate intake by sex (and pregnancy), plus about 0.75 L per hour of exercise and 0.5 L in hot weather; about 80% from drinks.

Method and assumptions

The adequate intakes are from the National Academies’ Dietary Reference Intakes for water. Sweat losses during exercise vary widely, roughly 0.5 to 1.5 L an hour; weighing yourself before and after exercise shows your own loss.

Questions

How much water should a man drink a day?

About 3 L (13 cups) from drinks, and more with 45 minutes of exercise.

Sources

Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.

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