Water intake at 100 lb
This calculator turns weight and exercise into a daily water target. The sample person weighs 100 lb with 30 minutes of exercise.
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. This page converts 100 lb to 45.36 kg first, with 30 minutes of exercise.
Worked example
A person at 100 lb with 30 minutes of exercise is 45.36 kg. Multiply by 35: 45.36 × 35 = 1587.6 ml. Exercise adds 350 × 30 divided by 30 = 350 ml. The total is 1937.6 ml, or 1.94 liters. In ounces that is 1937.6 divided by 29.5735, which is 65.5. In cups it is 8.2.
Common questions
What if I exercise more or less than this?
Change the exercise minutes. Each 30 minutes adds 350 milliliters. At 30 minutes the page adds 350 ml. An extra 30 minutes would bring the total to 2287.6 ml.
Is 35 milliliters per kilogram right for everyone?
No. It is a common starting estimate. Heat, illness, pregnancy and some health conditions change needs. For 100 lb the starting figure is 1587.6 ml before exercise, and 1937.6 ml with 30 minutes of exercise.
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. At 100 lb with 30 minutes of exercise, spread over 16 waking hours, 1.94 liters is about 121 ml an hour.
How many ounces or cups is that?
A US fluid ounce is 29.5735 milliliters and a cup is 8 ounces. At 100 lb with 30 minutes of exercise, 1937.6 ml is 65.5 ounces or 8.2 cups.
Do coffee and tea count toward my water?
Most drinks count toward your fluid total, though plain water is the simplest choice. At 100 lb with 30 minutes of exercise, 1.94 liters a day is about 8 cups spread across the day.