What is a Body Fat Scale?

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We are all familiar with the traditional body weight scale. But did you know there’s such a thing as a body fat scale? So, what is a body fat scale?

When you hear diet or exercise, one of the first things that come to mind is weight loss. But more important than weight loss is fat loss. Doctors and exercise coaches are in agreement on just how bad excessive fat can be to your health. That is why we have all these tests, devices, and formulas that measure how much body fat we have in our body.

Long before technological advances touched the once-forgotten weight scale, people either had to go to the doctor’s office to get a bioelectrical impedance analysis or to the gym to get their skin caliper measurements and learn about their body fat percentage (BFP). Thankfully, we now have BFP scales that allow us to monitor our body fat percentage at the comfort of our home anytime and without putting a hole in our pockets.

Why Do We Need to Get Rid of Excessive Fat?

We’ve all heard that ‘fat is beautiful’ and we’ve seen all these campaigns about embracing people of all shapes and sizes. While all that sounds great and politically-correct, science begs to differ especially with looking on excessive fat kindly. When you have too much fat in your body, you risk yourself in developing the following:

  • certain cancers, including colon, breast, ovarian, and esophageal cancer
  • gallbladder diseases
  • gout
  • heart diseases and stroke
  • osteoarthritis
  • sleep apnea
  • type-2 diabetes

While the statement ‘fat is beautiful’ may be true, ‘fat but fit’ definitely isn’t.

What is Considered a Healthy Body Fat Percentage?

Body fat percentage (BFP) refers to the amount of fat in relation to our body mass. The table below shows that having body fat isn’t necessarily a bad thing. In fact, a woman is in the pink if she has 21% to 24% BFP; so is a man with a 14% to 17% of BFP. But going over the 31% mark for women and 25% line for men is not.

Essential Fat10-13%2-5%
Typical Athletes14-20%6-13%
Fitness (In Shape)21-24%14-17%

Source: American Council on Exercise Guidelines

Another important thing to remember about body fat is that it’s not just how much body fat you have but also where you have them mostly. Visceral fat, or fat around the stomach, particularly is dangerous. It hides in the spaces between the abdominal organs, creates metabolic disturbances, and causes some serious health problems.

What are the Different Ways to Know Your Body Fat Percentage?

Before going down to the nitty-gritty of what is a body fat scale, first, let’s see how body fat percentage is tested or computed to better appreciate the purpose of a body fat scale. Below are just some of popular ways of getting your BFP:

The Hydrostatic Weighing Method

Also called underwater weighing, this clinical BFP test compares your bodyweight outside the water and while submerged in water. Together with the water density, the bodyweight values will reveal a reliable body composition estimate. The procedure includes having you exhale as much air out of your lungs and making you sit completely submerged underwater. All that discomfort also comes at a hefty price.

The Bioelectrical Impedance Analysis

The bioelectrical impedance analysis is a test that involves a weak electrical current that you could barely feel. The idea is for electricity to run up one part of the body and go down the other side. If you have more fat, which is a poor conductor of electricity, electrical impulses will take longer to reach the other side because of the resistance or impedance. Conversely, if you have less fat, electricity can travel faster since there’s less resistance or impedance.

While this provides a more affordable, more comfortable, and faster way of calculating BFP than underwater weighing, it’s not nearly as accurate.

The Body Fat or Skin Caliper Method

It’s a skin fold assessment performed on three or seven areas of the body using a skin caliper. After you have determined the values in mm, you plug the sum of all those areas in the formula below, including your age:

For men:

Body Density = 1.112 – (0.00043499 * SUM7) + (0.00000055 * SUM7²) – (0.00028826 * Age)

Body Fat Percentage = [(4.95/Bone Density) – 4.5] 100

For women:

Body Density = 1.097 – (0.00046971 * SUM7) + (0.00000056 * SUM7²) – (0.00012828 * AGE)

Body Fat Percentage = [(4.95/Bone Density) – 4.5] 100

Note: The formula above is for seven sites/areas.

The rationale behind this device is that the thicker the skin fold is, the more fat there is underlying the skin. Its reliability though is highly dependent on the consistency of the person taking the measurements and of the area being monitored. Another variable is that fat may accumulate in other parts of the body for other individuals. A skin caliper may cost you anywhere between $10 to $500.

The Modified YMCA Method

This DIY method requires only a weight scale and a tape measure. You need values for your weight in pounds, as well as the circumferences of your waist; at smallest point, hips; at the fullest point, forearm; at the fullest point, and wrist; at the thinnest point, in inches. To compute, enter the figures in the applicable formula:

For male:

Lean Body Weight (in pounds) = (1.082 x total weight) – (4.15 x waist measurement) + 94.42

For female:

Lean Body Weight (in pounds) = (0.732 x total weight) – (0.157 x waist measurement) – (0.249 x hip measurement) + (0.434 x forearm measurement) + (wrist measurement / 3.14) + 8.987

Then, convert your lean body mass weight to body fat percentage using this:

Body Fat Percentage = (body weight – lean body mass) / (body weight) x 100

For prime results, measurements must be taken consistently first thing in the morning.

The Department of Defense’s (DoD) Method

Also called as the US Navy Circumference Method, it is another DIY method for calculating BFP. The values you need are height in inches, as well as waist; at the smallest point, hip; at the fullest point, and neck circumference; below Adam’s apple, in inches. Then, using a scientific calculator, plug in the values in the given formula below:

For male:

Body Fat Percentage = 86.01 × Log10 (waist measurement – neck measurement) – 70.041 × Log10 (height measurement) + 36.76 =

For female:

Body Fat Percentage = 163.205 × Log10 (waist measurement + hip measurement – neck measurement) – 97.684 × Log10 (height measurement) – 78.387

If the numbers are making you dizzy, there are online calculators to help you compute your BFP. All you need to do is enter the figures.

So, What is a Body Fat Scale and How Does it Work?

Now, not everyone has the time for and money to spend on an expensive yet reliable hydrostatic weighing test. Neither does everyone have the time, skill, nor patience to perform the DIY body fat percentage measurements and calculations. Thankfully, there’s a more affordable and convenient option in the form of a body fat scale. So, what is a body fat scale and how does it work?

Using the same technology in bioelectrical impedance analysis, the body fat scale sends an imperceptible electrical current up one leg and down the other. It reveals your body fat percentage based on the impedance or resistance that the electrical current meets before it successfully crosses the other foot. In principle, the longer it takes, the more fat there is. The resistance information, together with the height, weight, age, and gender data, will provide you an estimated body fat percentage.

What Features Do Body Fat Scales Have?

There is a wide range of Digital Body Fat Scales available, and they have different offerings regarding the following:

  • Weight Capacity. If you’re buying a BFP home scale, you have to make sure that the device can support your weight. Some of these digital home scales can support only up to 300 pounds. The sturdier ones can go as high as 440 pounds.
  • Measurement Options. Aside from body fat percentage, some BFP scales can also compute visceral fat, BMI, bone and muscle mass, water weight, and metabolic age measurements, among others.
  • Data storage capacity. Depending on how small or big your family is, you can find a BFP scale that can store information for 8 to 16 users.
  • Advance Technology. Different brands and makes of digital BFP home scales outdo each other in terms of smart features. Bluetooth or WiFi connectivity, auto user recognition, touch screen interface, a baby weighing mode, and a smart app synchronization capability with fitness apps, are just some of them.
  • Precision sensors. Of course, the most important feature your digital body fat scale must possess is the ability to provide accurate results. This will heavily rely on the kind of sensors your scales are equipped with. 

Just How Reliable are these BFP Home Scales?

Since the electrical current runs only from foot to foot, it means that only the fat content in the lower body is measured. And because people come in different shapes and store fat differently, these scales aren’t that reliable just like the other methods. At best, they can be 80% correct. Nevertheless, they can still come in handy in tracking your fat loss progress.

Tips on Using Your BFP Home Scale

To maximize the use of your body fat home scale, there are certain things to take note of:

Find a scale that works for your needs.

If you’re the no-fuss person, find a simple BFP scale. If it motivates you to see a graph of your progress, then use one that allows you to sync the scale readings with a smart app. If you’re an athlete, get a digital BFP scale for sportspeople.

Put the scales on a hard, level floor.

Scales perform better on them than on carpeted surfaces.

Be consistent

May it be on the time of the day you take your measurement, the room temperature, or your fluid or food intake. If you want relatively reliable results, you need to remove as many variables as you can that may affect the reading.

Use it as a way to track your progress.

Don’t see the results as definitive. If possible, get one hydrostatic weight analysis or skin caliper measurement as a point of reference or comparison to your scale’s readings.

Clean your feet and the foot pads thoroughly before and after use.

The sensor pads will work better if there’s good contact with your feet.

Don’t test immediately after exercising, eating, or drinking.

Hydration levels may affect the results. Wait for 24 hours after a strenuous exercise and an hour after drinking or eating before stepping on the scales.

Do not use when pregnant or if you have a pacemaker.

Although you cannot feel the electricity, it may have a negative impact on your baby or interfere with your implant device. Metal plates and screws in your body may skew the results as well.


By now you would have realized that the strongest selling point of a body fat percentage home scale is not its reliability. Just like most BFP methods, the results are not definitive. Nevertheless, getting one will save you trips to the doctor or to the gym to take Body Fat Percentage tests. Not to mention, that will save you a lot of money.

Most important, these scales will keep you motivated and focused on your fat loss goal. And if you get the ones with all the bells and whistles, you’ll be able to track more than just your body fat mass. With all the features that come with the new generation of body fat percentage home scales, you are sure to find one good companion on your journey to fitness and wellness.

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