How Much Water Should You Drink Daily?
Learn science-based hydration guidelines, how to calculate your personal water needs, and signs of dehydration.
General Guidelines
The popular advice to drink 'eight glasses of water a day,' which works out to about 2 liters, is a reasonable starting point but is also an oversimplification. The National Academies of Sciences, Engineering, and Medicine provides more nuanced recommendations: approximately 3.7 liters (125 ounces) of total daily fluid for men and 2.7 liters (91 ounces) for women. The critical word is 'total,' because this includes water from all sources, not just what you drink from a glass.
Factors That Increase Your Water Needs
Several factors can increase your body's water requirements above the general guidelines.
Signs of Dehydration to Watch For
Your body provides several signals when it needs more water. Thirst is the most obvious, but by the time you feel thirsty, you are already mildly dehydrated.
Practical Tips for Staying Hydrated
Building hydration habits into your daily routine is more effective than trying to drink a large quantity of water all at once.