Different Ways To Measure Body Fat

Different Ways To Measure Body Fat
February 28, 2014 8:48 AM

Are you concerned about your body weight but not sure how to measure your body fat? Don’t worry. Just read this article as it will inform you about some ways to measure body fat.

Body fat percentage is the amount of fat present in a person’s body in comparison to everything else (including the muscles, water, tendons, bones etc.). However, measuring body fat isn’t easy.

That’s why different methods of measuring the body fat have been found through research. Each of these methods will be briefly discussed in the next few paragraphs.

Skin Calipers

Using skin calipers to measure body fat is probably the most accessible method. It is a skin fold assessment and can be done from three, four, or even places of the body. Skin calipers are mostly used by technicians for measuring a person’s body fat. The technician first of all pinches the skin and then uses the caliper device to measure thickness level of different sites including abdomen, arms, chest and thighs. After that, it is put into a formula to measure the total fat percentage of the body.

Pros and Cons

Since it is relatively inexpensive, skin calipers is the most accessible method of measuring body fat. Moreover, skin calipers are easily available in the market. However there are some cons of using skin calipers too. Since this method relies on accurate readings from a few sites of the body, its margin of error can vary depending upon the technician’s skills.

Although this instrument measures body fat from the main parts of body, a person having fat outside the measured areas will end up with a lower reading.

Hydrostatic weighing

This method compares a person’s normal body weight to his body weight under water. From these two numbers and the density of water, the person’s density is measured, which is then used for measuring body weight composition.

Pros and Cons

This method is an accurate one as it uses true variables and therefore, has a low percentage of error. However a problem with this method is its inconvenience. Unless a person has some underwater measuring method at home, he will have to go to a lab to measure body fat. Moreover it is also expensive in comparison to skin calipers.

DEXA (Dual Energy X-Ray Absorptiometry)

A DEXA scan exposes a person to X-ray beams of different intensities. In this method, a patient lies still while a machine emits high and low energy X-ray beams, which pass through his entire body. This machine also has the ability to scan each body part individually.

Pros and Cons

This method, like the hydrostatic method is accurate. It has an advantage over hydrostatic method which is that a person doesn’t have to go under water. However, it is also a bit inconvenient in the sense that a person has to make an appointment.

Air Displacement Method

The device used for measuring body fat in this case is Bod Pod which uses Archimedes principle. A chamber is used for measuring body fat. First the volume of chamber is measured while it is empty. After that volume is measured with the person inside. Subtracting these two volumes gives the person’s body volume. After that body density can be computed and from there body composition is found out.

Pros and Cons

Some pros of using air displacement method include high level of accuracy, fast test time and ease of usage. This method is suited for people of all ages. However a problem with this method is that it is quite expensive and only some research laboratories offer it.

Bioelectrical Impedance

In this method, electrodes are used. The scales of electrodes can either be simple (electrodes on each of the foot) or complex (a scale involving handholds with additional electrodes). This device works by sending electrical impulses throughout the body and measuring their return. A leaner body tissue will give a faster time response as compared to a fat body tissue.

Pros and Cons

A major advantage of this method is that it is quite inexpensive. The electrodes are also available in some gyms. Moreover no particular practice is needed. Only a button has to be pressed and measurements are done in a matter of seconds. However, the major issue with this device is that of accuracy, making it a bit unreliable.

Calculating Body Fat Through BMI

An individual’s body fat can also be measured through the Body Mass Index (BMI) method. The BMI of a person is a person’s weight in kilograms divided by the square of height in meters.

A number of formulas have been given by researchers for calculating body fat all of which are based on researches published in journals.

The following formulas are used for calculating body fat from BMI.

Child Body Fat% = (1.51 x BMI) – (0.70 x Age) – (3.6 x sex) + 1.4 Adult Body Fat% = (1.20 x BMI) + (0.23 x Age) – (10.8 x sex) – 5.4 where sex is 1 for male and 0 for females.

Calculating Body Fat through Body Weight

Body fat percentage can also be calculated through body weight. There are separate methods for men and women which are mentioned below:

For Men

  1. Before performing the calculations, you need to know the body weight and waist girth. Multiply the body weight with 1.082 and add the result to 94.42. Save this number. The calculation is this: (body weight x 1.082) + 94.42 = result 1
  2. Multiply the waist girth with 4.15. Subtract this number from the result 1. The result obtained is your lean body weight, that is, result 1 – (weight girth x 4.15) = Lean Body Weight
  3. Subtract lean body weight from the total body weight (Total weight – lean body weight). Now multiply this number with 100. Now divide your result by the total body weight. The final answer will give the body percentage fat. ((Total Body Weight – Lean Body Weight) x 100) / Body Weight = body fat percentage.

For Women

Before calculating the body fat percentage for women, five measurements are needed which include body weight, wrist circumference, hip circumference, forearm circumference and the waist circumference.

  1. Multiply bodyweight with 0.732. Body weight x .0732 = result 1
  2. Add the resultant to 8.987. result1 + 8.987 = result 2
  3. Divide wrist circumference by 3.14. wrist / 3.14 = result 3
  4. Multiply the waist measurement by 0.157. waist x 0.157 = result 4
  5. Multiply hip measurement by 0.249. Hip x 0.249 = result 5
  6. Multiply forearm measurement by 0.434. forearm x 0.434 = result 6
  7. Add the result 2 and result 3. result 2 + result 3 = result 7
  8. Subtract result 4 from result 7. result 7 – result 4 = result 8
  9. Subtract result 5 from result 8. result 8 – result 5 = result 9
  10. Add result 6 and result 9 which will give you your lean body mass. Result 6 + result 9 = lean body mass
  11. Subtract lean body mass from body weight. Multiply this number by 100 and divide it by your body weight. ((body weight – lean body mass) x 100) / body weight.


This article has mentioned some ways to measure body fat. Use one of the methods above to measure the amount of fat in your body.

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Written by: Michal Vilímovský (EN)
Education: Medical student, 3rd Faculty of Medicine, Charles University, Prague, Czech Republic
Published: February 28, 2014 8:48 AM
Next scheduled update: February 28, 2016 8:48 AM
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