Guides
2 so far, newest first.
◌ Water intake
Does coffee count as water intake? Yes, mostly
Yes. A cup of coffee is mostly water, and at everyday amounts caffeine's effect on urine is small, so coffee and tea count toward your daily total.
◌ Water intake
How much water should you drink a day? The honest answer
About 2.7 litres of total water a day for women and 3.7 for men, food and drinks included, per the U.S. National Academies. Eight glasses is a slogan.
What the guides say
The short version of each, before you read it.
Does coffee count as water intake? Yes, mostly
- Yes, coffee counts as water intake. A cup is about 98 percent water and the fluid stays with you.
- In a 2014 trial, four cups of coffee a day left total body water and urine output unchanged against four cups of water.
- A meta-analysis of 16 studies found caffeine raises urine volume about 16 percent on average, well short of the drink's volume, and not at all after exercise.
- The real ceiling is caffeine: the FDA cites 400 milligrams a day, about two to three cups, for healthy adults. Decaf and tea carry far less.
How much water should you drink a day? The honest answer
- About 2.7 litres a day of total water for women and 3.7 for men, food and drinks included (U.S. National Academies).
- Roughly a fifth of that arrives in food, so aim for nine to thirteen cups of drinks depending on size, activity and heat.
- Coffee and tea count. Alcohol works against you.
- Thirst and pale-yellow urine are the everyday signals; a personal estimate is 30 to 35 ml per kilogram.
