Water intake calculator
How much water to drink a day in cups, ounces and liters, from the National Academies Adequate Intake.
- ๐บ๐ธ US federal & state rules
- See sources
Water from drinks a day
12.7 cups
101 fl oz or 3 liters of water and other beverages
- Total water, food included
- 15.6 cups (125 fl oz, 3.7 L)
- From food (about 20%)
- 0.7 L
- Group
- Men 19 and older
This is an example. Enter your numbers above and press the button to see your own result.
Adequate Intake by group (total, of which from drinks)
| Men 19 and older | 3.7 L total, 3 L from drinks (12.7 cups) |
|---|---|
| Women 19 and older | 2.7 L total, 2.2 L from drinks (9.3 cups) |
| Pregnancy | 3 L total, 2.3 L from drinks (9.7 cups) |
| Breastfeeding | 3.8 L total, 3.1 L from drinks (13.1 cups) |
- These are the National Academies Adequate Intakes for adults. All drinks count, including coffee, tea and milk.
- People who exercise hard or live in hot climates may need more. Very active people in hot weather can need 6 liters or more a day.
- Thirst is a good guide for most healthy people. There is no set upper limit, but drinking far more than you sweat out in a short time can be dangerous.
- This is an estimate for general information, not medical advice. Talk to a doctor or registered dietitian before a big change in diet or exercise, especially if you are pregnant or have a health condition.
Show the math
| Adequate Intake (total) | 3.7 L ร 33.814 = 125.1 fl oz = 15.6 cups |
|---|---|
| From drinks | 3 L ร 33.814 = 101.4 fl oz = 12.7 cups |
What to do next
How it works
The calculator shows the Adequate Intake for total water from the National Academies 2004 report. Total water includes drinks and the water in food. About 80% usually comes from drinks, so the main result is the drink portion in cups (8 fl oz), fluid ounces and liters.
Things to keep in mind
An Adequate Intake is based on what healthy people in a temperate climate actually drink. It is not a minimum, and most healthy people meet their needs by drinking when thirsty and with meals.
You need more in heat, at altitude and during long workouts. Some conditions, such as heart failure or kidney disease, call for limits on fluid, so follow your doctor if you have been told to restrict water. This page is not medical advice.
Sources
Frequently asked questions
How much water should I drink a day?
The National Academies set total water at 3.7 liters for men and 2.7 liters for women, food included. From drinks alone that is about 3.0 liters (12.7 cups) for men and 2.2 liters (9.3 cups) for women.
Is 8 glasses of water a day right?
It is a rough rule, not an official one. For women the drink figure of 9.3 cups is close to 8 glasses. Men need more, about 12.7 cups from drinks.
Does coffee count toward water intake?
Yes. The Adequate Intake counts all beverages, including coffee, tea and milk, plus the water in food.
How much water when pregnant or breastfeeding?
Pregnancy: 3.0 liters total, about 2.3 liters (9.7 cups) from drinks. Breastfeeding: 3.8 liters total, about 3.1 liters (13.1 cups) from drinks.