How To Calculate Body Fat Percentage: Your Ultimate Guide

Are you wondering how to calculate body fat percentage? You’ve come to the right place. But before we answer that question, let’s examine why understanding body fat is important.

Imagine this scenario: A first-time gym-goer struts into the gym. They meet with a personal trainer, and when asked about their goals, reply with a simple, "I want to lose weight."

What's wrong with this picture?

While wanting to lose weight can be a gateway to the wellness community, it often comes with a few problems. First, weight is not a clear depiction of overall health. For example, a six-foot man with a low BMI (body mass index) could weigh the same as a 5'8” man with a high BMI.

In simpler terms, body weight is just a number; it doesn't tell you what goes into that weight. It doesn't tell you how much muscle mass, body fat, or bone tissue accounts for that weight. This, in turn, can skew someone’s fitness goals. 

For example, someone with a lower amount of body fat will have less weight to lose. Contrarily, someone with a low amount of muscle may become frustrated when they don't lose weight (because they're gaining muscle due to strength training).

In the context of health and fitness, one's body fat percentage is a far better measure of health than their body weight. Below, we explain what body fat is, how to calculate body fat percentage, and different tools to measure body fat.

What Is Body Fat? 

Body fat is — just as the name entails — the fat inside your body. The scientific term for body fat is “adipose tissue.” 

Athletes and bodybuilders put countless hours in at the gym trying to erase any trace of body fat they have. While some body fat is essential for proper health and longevity, a high amount of body fat — particularly belly fat — can lead to obesity, metabolic syndrome, heart disease, type 2 diabetes, and stroke. 

So, how much body fat is too much? How much is too little?

What Is a Healthy Body Fat Percentage?

While many people in the United States are concerned with weight loss or having too much body fat, having too little body fat comes with its own set of concerns.

Body fat provides insulation (keeps you warm), protects your organs, and serves as a source of long-term energy. As published by the University of New Mexico, the levels of essential body fat for men and women equal 5% and 8%, respectively. This is the absolute minimum amount of body fat an individual can maintain.

That being said, many medical professionals will say the minimum levels of essential fat are far from healthy. For instance, falling below 5% (for men) and 15% (for women) disrupts basic biological processes. Women will stop menstruating if they fall below 15% total body fat, which can cause a decrease in bone density and other issues. As written in Medicine & Science in Sports & Exercise, this has caused a drastic (and quite alarming) increase in stress fractures in competitive female athletes.

Most male and female athletes are considered to have a healthy body composition when their percent body fat falls between 10-25% and 18-40%, restively. If you are a competitive athlete or a bodybuilder, your ideal body fat will fall between 12-18% (for men) and 16-25% (for women). 

How to Calculate Body Fat Percentage

Unlike calculating your weight, you can't simply step on a scale and know your body fat percentage.

To calculate your body fat, you'll need a tool, such as a fat caliper, body fat scale, or full-body scan (such as a DEXA scan). Below, we dive into a number of methods to calculate body fat and the accuracy of each. 

1. Body Fat Calculator 

To use a body fat calculator, you'll need a flexible tape measure (sometimes found in the sewing section of retailers) and an online calculator. 

Here's how to calculate body fat percentage with a calculator: Step on a regular body weight scale and record your weight. Next, using the tape measure, measure the circumference of your waist, wrist, and forearm. Enter all measurements into the online calculator to retrieve your body fat. 

A body fat calculator is the least accurate way to calculate body fat. If you carry a considerable amount of muscle mass, this could easily skew your results, with the calculator stating you have a higher amount of fat than you do.

2. Body Fat Calipers

Skinfold calipers pinch different areas of your body in order to measure body fat. This is a fairly inexpensive way to calculate body fat, and you could purchase a skinfold caliper online.

To use the calipers, pinch the fat on your triceps, hips, and thighs (if you're a woman), or your chest, abdominals, and thighs (if you're a man). Many calipers will have instructions on how to convert these skinfold measurements into body fat percentages. Otherwise, you can enter them online in a body fat percentage calculator.

The skinfold caliper method was originally designed by scientists Jackson and Pollock in the 1980s. As published in the International Journal of Body Composition Research, this is not the most accurate way to calculate body fat (although far more accurate than simply using a body fat calculator). You can expect a skinfold caliper to underestimate body fat by 2.1%. 

3. Hydrostatic Weighing

Hydrostatic weighing involves sitting in a chair, fully submerged in water. Your body density is recorded underwater, which is then used to calculate your body fat.

Underwater weighing can be fairly expensive and is usually not covered by insurance. However, it is considered to be the most accurate method to calculate body fat. 

4. Air Displacement (Plethysmography)

Air displacement plethysmography involves entering a large, egg-like machine called a BOD-POD. The BOD-POD covers your entire body and measures your weight and volume to calculate your body fat percentage.

According to an article written in the International Journal of Sports Medicine, a BOD-POD is a fairly accurate way to measure your body fat. However, the article also claims it significantly overestimates body fat ranges in comparison to hydrostatic weighing and skinfold calipers.

5. DEXA Scan

A DEXA Scan (dual-energy X-ray absorptiometry, also called a DXA scan) is a full-body scan that measures bone density. A DEXA scan uses an electromagnetic radiation to measure your entire body composition makeup — including fat mass, bone mass, water weight, and muscle mass.

You will need to visit a special facility to have a DEXA scan, and it can be expensive. According to the Journal of Sports Sciences, a DEXA scan is an extremely accurate way to calculate body fat percentage.

How to Calculate Body Fat Percentage Accurately

While many people begin their healthy journey hoping to lose weight, body weight is typically not the best measure of health. Understanding your body composition and body fat percentage is a far better depiction of your overall well being, with fat loss — not weight loss — being a more applicable goal.

There are numerous ways as to how to calculate body fat percentage. Body fat calculators and scales are usually the least optimal methods. Skinfold calipers are fairly accurate and reasonably priced, although your body fat percentage could be underestimated by several percentage points. Hydrostatic weighing, air displacement, and DEXA scans are considered to be the most accurate forms of measuring body fat — but they are pricier.