How to figure out how much water you should drink plus an easy way to track it

  • 3 Minutes Read

Eight glasses of water-is that really how much you should drink every day? Read on to learn about the factors impacting water needs, how much, how often, and how to know if you're on target.

How much should you drink

How much water you should drink is impacted by several factors

The "eight glasses of water a day" or "drink half your body weight in water" ideas may or may not be best suited for you. Several factors contribute to determining how much fluid you should consume, such as:

Role of water in the body

Although we can survive for weeks without food, we cannot survive for more than a few days without water. Body water allows us to regulate our core temperature to get neither too hot nor too cold. Body water is also critical for many body processes, including:

How much should you drink each day? Use these water calculators to find out

Method 1:

The first calculation method figures your daily fluid needs based on your calorie intake. You'll want to get in one milliliter (ml) of water for every one calorie you consume. For example, perhaps your weight maintenance calorie target is 2,200 calories/day. Then your water intake (from both food and liquid sources) should be approximately 2,200 ml/day (just over two quarts). Make sure to set your fluid goal higher if you exercise for a long duration in a hot environment. And of course, if you are thirsty, listen to your body! Don't stop drinking water just because you met your hydration target for the day.

Method 2:

The second calculation method figures your daily fluid needs based on your body weight and age. Body water decreases by about 15% from age 20-80. Many people struggle to stay hydrated as they age due to changes in thirst perception.

Age: Young adult 16 to 30 years
Water per unit of body weight: 0.54 - 0.6 fl. oz./lb.

Age: Adult 31 to 54 years
Water per unit of body weight: 0.46 - 0.54 fl. oz./lb.

Age: Adult 55 to 65 years
Water per unit of body weight: 0.46 fl. oz./lb.

Age: Adult > 65 years
Water per unit of body weight: 0.38 fl. oz./lb.

Example: If you are a 47-year-old adult who weighs 60 kg (132 lbs.), your water intake should be about 61-71 ounces (about two quarts)/day.

Water requirement calculations are from the Academy of Nutrition and Dietetics.

Why is it important to track your water intake?

Tracking your water intake helps you see where you stand compared to your goals. If you are curious where you stand in regards to hydration, consider tracking.

When you know (through tracking) that you're getting enough water, you realize what experts already know. It helps you feel energized, helps your skin to appear more youthful, and it can help you feel full without adding extra calories.

Keeping track using the MyNetDiary app

The MyNetDiary app makes it easy to track hydration. The Water Tracker feature is available on iPhone, Android, and web apps.

Did you know that you can count all non-alcoholic beverages towards your daily water requirement?

Simply tap the water glass icon on your dashboard. Unless you specify otherwise, the app's default glass size is eight fluid ounces(237 ml). For example, if you drink a cup of tea, tap one glass icon.

Also, the Water Tracker feature allows you to customize how much you should drink each day and displays a graph to easily monitor how you're doing (see below).

Note: When you sync MyNetDiary with iOS Health app, the total volume of water comes from the sum of all filled water glass icons.

If you tend to forget to drink water, MyNetDiary covers that, too! Simply enable Water Reminders under Settings in the Water dashboard. Plus you can schedule the frequency and time range of reminders for further customization (see below).

Signs of dehydration

If you are dehydrated, then start drinking! You might find it easier to tolerate drinking smaller volumes of water every 15 minutes or so rather than trying to guzzle a huge volume of water all at once. Then see what you can learn from this experience to recalculate how much you should drink to prevent dehydration from happening again.

Will I lose more weight if I drink more water?

If you replace a caloric beverage with water, then you will consume fewer calories. This could help you lose weight gradually, even if you changed nothing else in your diet. Suppose you stop drinking one 20-ounce bottle of root beer and replace it with 20 fluid ounces of water. Savings = 250 calories per day = 1750 calories per week = 7500 calories per month = two pounds per month!

Even if you simply add water to your daily intake, you might benefit from enhanced weight loss if drinking water prevents you from overeating.

Other hydration resources

Don't like the taste of water? Hydrate with these healthy drinks
Balance electrolytes naturally
Meet your hydration needs in the winter

Adapted from original content from Katherine Isacks, MPS, RDN, CDCES

Still new to MyNetDiary? Learn more today by downloading the app for FREE.

Apr 19, 2021
Joanna Kriehn
Joanna Kriehn, MS, RDN, CDE - Registered Dietitian Nutritionist and Certified Diabetes Educator (CDE)

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