Water intake calculators
This hub holds the water intake calculators. Pages below cover each body weight and three activity levels. Enter your weight and exercise time in the calculator below to see your daily water target. The worked example further down shows the steps with real numbers.
How it works
Multiply your weight in kilograms by 35 to get milliliters of water. Add 350 milliliters for every 30 minutes of exercise. The page converts the total to liters and ounces.
Worked example
Take a person who weighs 150 lb with 45 minutes of exercise. In metric that is 68.04 kg. Multiply by 35: 68.04 × 35 = 2381.4 ml. Exercise adds 350 × 45 divided by 30 = 525 ml. The total is 2906.4 ml. Divide by 1000 to get 2.91 liters. Divide 2906.4 by 29.5735 to get 98.3 ounces. Divide by 8 to get 12.3 cups.
Common questions
Is 35 milliliters per kilogram right for everyone?
No. It is a common starting estimate. Heat, illness, pregnancy and some health conditions change needs. Enter your own weight and exercise time in the calculator above to see your result.
Can I drink too much water?
Yes, though it is uncommon. Drinking far more than you need in a short time can dilute the salts in your blood. Spread your intake through the day. Enter your own weight and exercise time in the calculator above to see your result.
How many ounces or cups is that?
A US fluid ounce is 29.5735 milliliters and a cup is 8 ounces. Enter your own weight and exercise time in the calculator above to see your result.
Do coffee and tea count toward my water?
Most drinks count toward your fluid total, though plain water is the simplest choice. Enter your own weight and exercise time in the calculator above to see your result.
Does food count toward the total?
Food contains water. Treat the result as a goal for your total fluid across the day and not a quota for drinks alone. Enter your own weight and exercise time in the calculator above to see your result.