Water Intake Calculator

Learn how many ounces of water you should be drinking!

In just a few minutes you can calculate exactly how much water you need every day based on your body weight and activity level!

Water Calculator

Get my daily water needs with this 2 minute quiz

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How to Use this Water Calculator

Get your personal daily water goals in just a few minutes.

Just enter your details into the form above.

Then, we’ll send you your results on how many ounces and glasses of water per day you need to support your workouts and proper hydration levels.

Note: Results should not be used as a substitute for direct medical advice from your doctor or medical provider. Always check with your doctor for recommendations specific to your needs if you have a health problem influenced by water intake.

How Your Daily Water Needs are Calculated

Our hydration calculator uses a simple formula to quickly estimate your fluid needs. Here’s how it works:

Your general water requirements can be determined using your current body weight. Most people need to drink roughly half of their weight (in pounds) in ounces. For example, a 200-pound adult needs approximately 100 ounces of water each day.

Of course, your water needs will increase with any physical activity. So you’ll need to add 12 ounces of water for every 30 minutes of daily activity.

For example, a 200-pound adult who exercises for 45 minutes per day on average, will need roughly 168 ounces of water daily.

150 ounces + (12 x 1.5) = 168 ounces

Water needs can also fluctuate with the weather - you often need more fluids in hot and humid temperatures to reduce your risk of overheating.

Why Drinking Water is Important

Water is essential for survival. It is needed to support nearly every single bodily function including sleep and digesting and metabolizing food. It also plays a role in regulating body temperature and allowing your muscles and organs to function properly.

Water consumption can even support a healthy weight. Not only is water calorie-free, but drinking plenty of water, especially before meals, can help you decrease your calorie intake leading to weight loss.

Check out this article to learn more about how drinking water can help you lose weight.

Where Does Eight Glasses a Day Come From?

You might have heard the common advice telling you that we all need roughly eight glasses of water per day. This may seem like great common sense advice, but is it accurate?

The eight glasses a day rule comes from an influencer nutritionist by the name of Fredrick J. Stare. Although, this general guideline was never backed up by science and is still heavily debated to this day.

Eight glasses, or 64 ounces, of water daily might not be the right amount of water for everyone - general nutrition recommendations rarely work as a one-size-fits-all approach.

According to the National Academy of Science (NAS) and National Academy of Medicine (NAM), the recommended guideline for adults is 125 ounces for men and 91 ounces for women.

However, some of this (~20%) can come from food intake, so the adjusted recommendation is closer to 100 ounces for men and 75 ounces for women - both of which are higher than the eight glasses a day!

Are Your Drinking Enough Water?

Tracking your daily water intake using a nutrition tracking app is an easy way to tell if you are hitting your water goals each day. But you can also pay attention to how you feel and your urine output.

Even mild dehydration can negatively impact your workouts and health, so making sure you are staying on top of your fluids is key!

Signs of mild dehydration to watch out for can include: