Eight-by-Eight Rule from How Much Water Should You Be Drinking? (Slideshow)

How Much Water Should You Be Drinking? (Slideshow)

Your daily water requirement depends on 4 factors: body weight, dehydration, how much is lost, and activity level

Eight-by-Eight Rule


You’ve probably heard that drinking eight 8-ounce glasses of water a day is ideal. But actually, this is more of a recommendation than a rule to live by, as all of our bodies have different dietary needs. Still, it’s good to keep this number in mind as a general guideline. 



Your weight determines how much water you should be drinking daily. For example, someone who weighs 100 pounds doesn't need to drink as much water as someone who weighs 200 pounds. Keeping that in mind, your daily water requirement (in ounces) can be calculated by multiplying your weight by two-thirds. 


Use this simple formula: Weight x 2/3 = Ounces of Water You Should Drink Daily

Monitor Dehydration


Someone who is dehydrated requires more water. You can determine if you’re dehydrated by monitoring your urine as well as your bowel movements. If your urine isn’t a normal yellow color or if you’re suffering from constipation or hard, dense stools, you should drink more water. 

Replace What You Use


Considering the amount of water you lose when using the bathroom, breathing, and just living life, totaling about 2 to 3 liters a day, it’s necessary to drink more water to replace what you’ve lost.

Consider Your Activity Level


When you sweat, you lose water. You should add 12 ounces of water to your daily water intake for every 30 minutes of exercise.