For decades, we have relied on traditional body weight scales. The trouble is, they can only measure your weight and nothing else. It has become increasingly obvious that knowing your weight alone is not a particularly helpful metric when it comes to your overall health. As a result, body fat scales are becoming more popular because your body fat percentage is a far better indicator of your health.

Indeed, these scales are becoming increasingly more advanced and can now measure things such as water weight percentage, metabolic age, bone mass and much more.

How Do Body Fat Scales Work?

The vast majority of body fat scales use ‘bioelectrical impedance analysis’ (BIA) to read your results. A tiny electrical current is sent through the lower half of your body. This current is 100% safe and since it flows faster through muscle and water than fat and bone, the scale can then measure the current’s speed.

This number is used as part of a detailed mathematical formula which ultimately estimates your body fat. You will need to enter other data such as gender, age and height to get the reading. Although the current used is miniscule, you shouldn’t use one of these scales if you’re pregnant or have a pacemaker or defibrillator.

Are Body Fat Scales Accurate?

Body Fat Scales

This depends on who you ask! A number of health and fitness experts claim that body fat scales are not as accurate as other well-known body fat measurement methods (which we’ll outline below). According to a ‘Consumer Reports’ study, even the best scales are only accurate in 80% of cases. The main issue is that body fat scales can be thrown off by a wide range of factors which we explore below.


A big issue with body fat scales is the fact that you must remain perfectly still while the BIA process takes place. If you move or suddenly hop on the scales, an inaccurate result is likely. For best results, you must position your feet in the same location every time and stand completely still until the readings have been taken.


Remember, you need to stand barefoot on the scales so this can be an issue if you have foot calluses. You can forget about an accurate reading if you have thick calluses since they will block the electrical current.

Muscle Mass

Body fat scales can be especially imprecise if you’re a bodybuilder or have a muscular build. Muscle weighs more than fat which may lead to a higher body weight measurement. This can compromise the calculations made by the scale when it comes to measuring body fat percentage and Body Mass Index (BMI).


Eating or drinking can play havoc with your readings. This is also the case if you attempt to weigh yourself after exercise. If you are dehydrated or have lost water through sweat, there will be less water for the current to flow through. As a result, you’ll end up with a higher body fat reading than normal.

Likewise, if you drink too much fluid, are in the midst of your menstruation period or have a full bladder, you may end up with a lower than normal reading. To avoid this issue, weigh yourself once a week in the morning at the same time on the same day. It’s also best to measure yourself with no clothes on.

What Other Ways Can You Measure Your Body Fat Percentage?

Body Fat Percentage Chart

When it comes to using measurements to gauge your general health, avoid BMI as it doesn’t give you any clues in relation to body composition since it doesn’t calculate body fat. Fortunately, there are a wide variety of ways to measure your body fat percentage; some are more accurate than others.


Calipers are used by bodybuilders and it is believed to be one of the most accurate body fat testing methods. You use calipers to measure skinfold thickness at various points in the body. The most accurate method takes measurements from 7 points.

You should be able to get a measurement at your local fitness center; just make sure the person with the calipers knows what they are doing! It is quick, easy and very accurate when done correctly. However, the accuracy of calipers depends on the skill of the tester and some people have far more fat in certain areas than others which can skew the reading.


This used to be called Dual Energy X-Ray Absorptiometry (DEXA) and involves using a full body scanner and a pair of low dose x-rays to provide you with soft tissue mass and bone mass readings.

While it is a fast, effective and painless method, it is not offered at many locations and can cost up to $100.

Hydrostatic Weighing

This is also known as Underwater Weighing and involves comparing your weight outside the water to your weight while completely submerged underwater. These two readings are used along with the water’s density to determine your body’s density; then it is possible to estimate your body composition.

This is possibly the most accurate method of all but it costs up to $60 and you will struggle to find a facility that offers it.

Air Displacement Plethysmography

This isn’t dissimilar to Underwater Weighing insofar as your body’s density is measured. You sit in a small machine which measures your level of air displacement in order to find your density. This figure is then used to calculate your body composition. It is another accurate and comfortable test but it is again very expensive (up to $60 a time) and it is also hard to find a suitable location.


It’s very important to determine your body fat percentage because having an excess amount of fat in your body increases your risk of conditions such as high cholesterol, Type 2 diabetes and even cardiovascular problems.

Although body fat scales are not the most accurate tools on the market, they are convenient, relatively inexpensive and can at least give you a ballpark figure. An increasing number of people find that purchasing a body fat scale gives them the motivation to improve their health and fitness. Therefore, one of these digital scales could be a very shrewd purchase indeed.

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