What is Hydrostatic Weighing?

Calculating a body’s weight, and volume under the water is called Hydrostatic weighing. As by its definition, it is also called underwater weighing or hydro densitometry. Old and traditional scales do not provide accurate information about body fat. But the hydrostatic weighing depends on Archimedes principle that states ‘‘Any object partially or completely submerged into a fluid I.e., gas or liquid at rest is acted upon by an upward force; This force is equal to the fluid’s magnitude.’’ Besides modern methods of calculating body fat, hydrostatic weighing is one of the most accurate ways to calculate it. Stay in touch with us for more information about Hydrostatic weighing.

How Hydrostatic weighing is done?

As mentioned earlier, Hydrostatic weighing is one of the most accurate methods to calculate body fat. Many athletes and fitness lovers still consider hydrostatic weighing besides CT scan and MRI scan.

For hydrostatic weighing, firstly calculate your body weight on the land. After writing the accurate reading given by the scale on the land, the examiner will ask you to move slowly inside the water. Water is kept warm and lower to the chin so that you can easily breathe. Inside the water, there is a scaled chair; sit on this chair and breathe heavily in and out. The controller will note the underwater readings. Perform this act three to four times and then the examiner will find the average reading. The difference between the on-land weight and the underwater weight will allow the examiner to calculate your body fat. The following example will help you understand this procedure.

Consider, your body weight on land is 80 kgs but when you calculate it inside the water; it becomes 78 kgs which means your body displaces 2 liters of water. This weight difference shows that your body’s volume is 2 kgs.

Step-by-step this will be the procedure:

·         Calculate your body weight on land scale and let the examiner note the reading

·         Then slowly move inside the water tank

·         Sit on the chair inside the water. This chair will also have a scale to calculate your body weigh

·         Exhale all the air present inside the lungs and then hold your breath

·         Let the examiner note this reading as well

Perform this process 2 to 3 times. When the test is done, let the examiner calculate your body fat composition. The examiner will compare your land scale reading with underwater scale reading to provide an accurate result.

Advantages of Hydrostatic Weighing

Like we mentioned earlier, Hydrostatic weighing is one of the most accurate methods to calculate body fat. In modern ages, there are CT scans and MRI scans but these scans can have some side effects as well; to prevent these side effects, some people still prefer hydrostatic weighing. On the other hand, this is inexpensive and less time consuming. The whole process takes up to 15 to 20 minutes. This also helps people to maintain a proper diet because some people being thin can have more body fat and less muscle weight while on the other hand, some trained athletes can have lower body fats and more muscle weight.  These results can make someone happy or upset. However, hydrostatic weighing can be done anywhere with proper equipment; this is not like the other heavy machines present in medical centers. Some experts offer their services even at home. Give these experts your location and then they will reach out to you. They often have hydrostatic weighing mobile.

Why is hydrostatic body fat testing is done?

Underwater weighing has been considered the gold standard for body composition assessment. Scientific studies and research have proven that fats are lighter than bones and muscles. That is why we use hydrostatic weighing to calculate the body fat percentage corresponding to the water density. If the body has a higher fat ratio, then it will move upward by the force of water. But if the body consists of a lower fat ratio, then it will sink deeper in the water.

As discussed above, tests like MRI scans and CT scans can have side effects, and some people just do not find this suitable. Fitness enthusiasts prefer hydrostatic weighing to other medical procedures. On the other hand, no one likes to pay more; people also prefer underwater weighing because this is a lot less expensive than other tests out there.

Is an underwater weighing test being more accurate way to measure body fat?

The answer to this question relies on multiple factors. These factors make the result as accurate as possible. Before diving into those factors let us clear to you that hydrostatic weighing is considered the gold standard for body composition. There are other tests too like CT scan and MRI scan. These tests are limited to medical research, and are highly expensive. It is not that easy for one to go and have these tests. But on the other hand, one can perform hydrostatic weighing on his/ her will for health purposes. Now let’s dive into the factors affecting an accurate reading:


   If a person is not breathing properly and does not exhale all the air from his/ her lungs                 then it can cause an error in the reading. This will ultimately lead to a false result.

Bone density:

As we know that bones are heavier than fat. If the bone density will be higher than it can affect the result as well.


Hydrophobia means the fear of the water. Some people are afraid of the water and they still want to perform the test. This fear can cause instability. Some people cannot even submerge their selves inside the water; This type of issue can lead to a wrong end result.

However, if you have managed to overcome these little problems then the result will be accurate. The accuracy of the hydrostatic result is up to 98%. 

Drawbacks of Hydrostatic weighing:

Hydrostatic weighing or underwater weighing is still one of the best methods to find body fat composition. It is a really quick and inexpensive process. One can perform this process for his/ her health assurance. Hydrostatic weighing also provides relatively high accuracy that is up to 98%.

The only drawback of underwater weighing is that it is not suitable for every person to get completely submerged inside the water. People are often hydrophobic; this can lead to a false result. However, there is a minor risk of having a high bone density; this will increase the bone weigh and can cause an error in the final result.

Where to get a hydrostatic weighing test?

So, after knowing all about hydrostatic weighing; you want to take a test? if you want an accurate and inexpensive body composition test. Get yourself a Hydrostatic body fat test from Get Tanked Li which is located on a long island, 1626 Locus Avenue, Bohemia, NY.

You can book an online appointment. This will save you some time as well. A receptionist will receive your appointment details and will further guide you about the timings.