Free Body Fat Calculator - Precision Nutrition

How accurate is the body fat percentage calculator?

Pretty accurate, in general. But an online body fat calculator isn't the MOST accurate way to determine your body fat percentage.

There are many different methods you can use to calculate body fat percentage.

Here are the most common methods of measuring body fat, ranked from most accurate to least accurate.

1. DEXA scan

Dual Energy X-ray Absorptiometry (DEXA) involves using low-level X-rays to determine your fat-free mass, fat mass, and bone mineral density.

DEXA is the most accurate body fat measurement methodbut one drawback is that this method is not available in every geographic area, and it is relatively expensive compared to other methods.

2. Hydrostatic weighing

This method is first weighed, then weighed again while immersing in water. Because fat is less dense than water, a person with more body fat will weigh less underwater.

It's also a very accurate way of measuring body fat percentage (it was the gold standard before DEXA), but it is not commonly used outside of research settings. (This requires a tank that looks like a hot tub and, fun fact, an autopsy scale.)

3. Air displacement plethysmography (Bod Pod)

The machine estimates body fat percentage in a way similar to hydrostatic weighing, only using air pressure instead of water.

this method relatively accurate and more readily available (More and more gyms have them now), but they are more expensive than the less accurate options below.

4. Measurement of skin folds

Calipers are used to measure the thickness of fat and skin in various parts of the body. Then, these numbers are plugged into the formula to determine body fat percentage.

The accuracy of this method depends on the skill level of the person performing the measurement. In order to track changes over time, it is important that the same person takes all measurements.

Also, this method may not be accurate for those with very high body fat levels.

5. Circumference measurement

Body circumference measurements (as used in the body fat percentage calculator on this page) can be plugged into a formula with other information such as height, weight, age, and gender to estimate body fat percentage.

While that's not the most accurate approach, it is one of the easiest and requires no special equipment (other than a tape measure).

This method is especially useful for measuring progress over time, because changes in thickness can indicate changes in muscle mass and body fat.

6. Bioelectric impedance

Scales that measure body fat percentage use this method. Basically, a scale sends an electric current through your body and measures resistance.

Fat provides more resistance than muscle and water, which helps the scale estimate your body fat percentage.

Problem: This method is sensitive to hydration status. (So ​​your results can fluctuate even on the same day.)

7. Weight only

Changes in body weight may reflect a decrease or increase in body fat, but the scale won't tell you whether the weight gain or loss is from muscle or fat.

What's the deal with three body fat formulas?

As mentioned before, this body fat calculator takes your input and feeds it into three scientifically validated body fat percentage formulas:

  • YMCA Body Fat Formula: Originally used by the YMCA. Using waist circumference, weight, and gender.
  • Navy Body Fat Formula: Developed by the US Naval Health Research Center. Using neck and waist circumferences for men, and neck circumferences, waist circumferences and hip circumferences for women.1
  • CUN BAE Body Fat Formula: Developed at the University of Navarra in Spain. CUN BAE stands for Clinica Universidad de Navarra (CUN) Body Adiposity Estimator (BAE). It uses weight, height, age, and gender.2

We then average the three together to give you a solid picture of where you stand. Each body fat percentage formula has its advantages and disadvantages, so we use all three to come up with a more realistic estimate.

“My body fat estimate is ridiculous!”

OK, we've already noted that this body fat percentage calculator is just an approximation and, depending on your specific physique, may not accurately reflect your body fat percentage.

But let's explore this a little more.

Let's say a million random people use a calculator. Most likely, 950,000 of them would find that giving a pretty reliable estimate.

At the same time, it can go a long way — or completely Andtrusted—for 50,000 of those people.

Although 50,000 seems like a lot of people, compared to 950,000, it's a dime.

Think of it this way: In the general population, not many people—as a percentage—are built like NFL quarterbacks.

You, however, may be.

Or you may be on the other end of the body composition spectrum.

The formulas—like the one in this body fat calculator—that have been developed to estimate body fat percentage from circumference measurements are not sensitive enough to account for all body types, especially those far from average.

But… it is the best formula we have based on scientific research.

Again, these numbers don't define you. It's simply data you can use to measure changes over time.

Your age, gender and ethnicity affect your results.

People vary greatly in their body shape and size. We are all unique individuals.

In addition, there are several other factors that affect your body fat percentage and body fat distribution, including:

➤ Age

As you age, you tend to lose lean mass and gain body fat. You also tend to accumulate more visceral fat.

➤ Sex

On average, men and women tend to have different levels of body fat. Plus, that fat is often distributed in their bodies differently, thanks in large part to the effects of hormones.3,4,5,6

Men generally tend to be fatter around the midsection.

Females tend to gain weight around them lower abdomen, hips and thighs as well as in breast tissue.

However, men whose bodies convert testosterone to estrogen more easily may also gain fat in their breast tissue and around their hips and thighs, similar to the pattern of fat distribution in women.

Men and women tend to differ in how much body fat is optimal for health, function, longevity, and performance.

In general, female bodies prefer higher body fat ranges for overall health.

And, on average, men tend to be thinner over their lifetime than women.

What if I'm intersex or trans?

To date, there are no reliable calculations for intersex or transgender people. (This is due to a lack of scientific data in this area.)

Usually, the most accurate guess comes from using the closest body composition calculation to a one's current hormonal profile.7,8

Additional hormones such as estrogen And testosterone will, over time, affect your lean mass and body composition.

For example:

trans man who have been increasing testosterone for at least six months, and have had top surgery to remove breast tissue, may find the male body composition equation most accurate.

trans woman who have been supplementing with estrogen for at least six months may find the female body composition equation the most accurate.

➤ Ancestry/ethnicity

There may be meaningful differences between ethnic groups.9,10,11,12,13

This occurs both in terms of how accurately estimates of body fat calculations represent reality, and also for predicting health and disease risks.

For example, people with some types of South and East Asian ancestry may have a higher risk of metabolic disease (such as cardiovascular disease or type 2 diabetes) at relatively lower levels of body fat than someone of Western European descent.

And people from populations that typically have heavier, denser bodies—such as many South Pacific natives—can be categorized as “obese” or in the high-risk category, even though these body types are not associated with negative health effects. for them.