Back to Blog

What Is Total Body Water?

What Is Total Body Water?

As part of our ‘understanding your body composition scale measurements’ series, we’re taking a closer look at every reading on our body composition scale.

For this blog post we’re going to cover what Total Body Water (TBW) is and why it’s important.



What is Body Water?

Body water is essential in every system and function of the body.

That’s why, starting from birth, more than half of your body weight will be made up of water. This will vary with age and water consumption, but, on average, your water will consistently make up 50% of your body weight.

Babies have the highest store of body water, while adults older have the lowest percentage.

Percentage of Body Made up of Water
Where is Body Water Stored?

Now that you know our bodies are made up of more than 50% water, you may be wondering, where is this water stored?

Water is predominantly stored in organs and cells around our body. This is known as intracellular water.

Brains and kidneys store the highest percentage of water, probably because they need it the most. Teeth, on the other hand, have the lowest water percentage.

Some water is also stored outside of the cells, which is known as extracellular water.



What is Total Body Water?

Total Body Water or Body Water percentage is the total amount of water in the human body.

This includes fluids both inside and outside of cells.


What is Extracellular Water?

As mentioned earlier, extracellular water is water located outside of your cells.

This makes up roughly ⅓ of your total body water and is important for delivering oxygen to your cells.


What is Intracellular Water?

On the other hand, intracellular water is water found inside your cells.

Intracellular water encompasses the remaining ⅔ of your total body water but this figure can be skewed.


What is the ideal Total Body Water ratio?

As we mentioned earlier, the percentage of water in your body changes as you age and can also be affected by your body composition. Therefore, the percentages that follow are just an average.

An adult woman’s body water percentage should fall between 40% and 60%.

For an adult male, it will fluctuate between 50% and 65% of the total body weight.

If you’re older than 50 then your total body water will likely be lower than this and may lie anywhere between 40% and 65%.

Average Healthy Body Water Percentage for Males and Females

For pregnant women, your body water percentage is likely to be significantly higher.

Additionally, lean tissue contains more water than fatty tissue. So the more unfit you are, the less water your body will contain.

It’s also important to note that a healthy range of intracellular water to extracellular water is 3:2. If this balance is not present it can cause changes in your health both negatively and positively depending on which water is increasing.



How do you Calculate Your Total Body Water?

Total Body Water can be measured in a number of ways.

The easiest way is to use a body composition scale as it is quick, easy and likely to be the most accurate.

You can also use an online calculator such as this one from omni calculator.

Finally, you can also use the Watson formula:


Watson Formula for Men

2.447 – (0.09145 x age) + (0.1074 x height in centimetres) + (0.3362 x weight in kilograms) = total body water (TBW) in litres.


Watson Formula for Women

–2.097 + (0.1069 x height in centimetres) + (0.2466 x weight in kilograms) = total body weight (TBW) in litres.



Why Is Water Important For the Body?

Water is essential for almost all body functions, so it’s important that you’re drinking enough water every day.

Water is used in functions such as:

  • Removing waste
  • Protecting sensitive tissue
  • Regulating temperature
  • Protecting the spinal cord
  • Keeping joints lubricated
  • Producing saliva
  • Metabolising and transporting proteins
  • Surrounds the baby in the womb for protection.



What Are the Consequences of Not Having Enough Water?

There are a number of risks of dehydration. The most serious are:

  • Heat stroke
  • UTI
  • Kidney stones
  • Seizures
  • Sudden drops in blood pressure



What are the Symptoms of Dehydration?

If you’re not drinking enough water to support your water levels then you’ll enter a state of dehydration.

There are a number of signs of dehydration, including:

  • Tiredness
  • Dark yellow urine
  • Feeling thirsty
  • Dry mouth and lips
  • Feeling dizzy or light-headed
  • Headaches
  • Muscle Cramps

One interesting fact is that if you’re feeling thirsty then you’re already dehydrated.



What Can I Do to Improve My Water Consumption?

It is recommended to drink 11 cups of water a day for women and 16 cups of water a day for men, in order to maintain a healthy amount of water in your body. But this may increase if you do regular exercise.

This does not include soda, juice or other sugar-sweetened drinks as they don’t provide substantial water and may actually harm our health.

You should also try to eat foods that are high in water content, such as cucumber, tomatoes, broccoli and oranges.



Further Reading

Total Body Water is just one of the measurements a body composition scale can show you. . Find a complete list of body composition scale readings, what they mean and their healthy averages here.

Knowing your protein mass can be key when calculating how much water you need to drink. Find out what lean mass is and how much you should have in this blog post.

Body fat percentage is another popular reading on body composition scales. In this ultimate guide, we look at the healthy ranges for men and women, and how to calculate it.