Goodbye, BMI: Your Guide to Reading a Skinfold Caliper

Body fat skinfold test for adults, using caliper on an upper arm, over biceps muscle

Key Points

  • The body fat caliper is a simple, affordable, and trusted device that makes calculating your body fat percentage accessible to all.

  • There are multiple methods of using a body fat caliper, but all are very similar and require the same tools.

  • The body fat caliper is not an exact science, so your technique is essential when using the device.

Whether you’re a fitness enthusiast or just looking to keep your health in check, you’ve probably been curious about your body fat percentage. Maybe you’re even more than curious; maybe your most recent Body Mass Index (BMI) number had you sprinting to the gym to work up a sweat, or you’re monitoring your levels for health reasons. Either way, it seems like there should be a simple way for the average person to find their body fat percentage.

And there is — by reading a body fat caliper.

The body fat caliper is one of the most accessible ways to find your body fat percentage. Read on to learn how to use one.

Doctor measures abdominal fat with skinfold caplipers

Body Fat Calipers: The Basics

First things first: What is a caliper? 

Often referred to as a body fat caliper or a skinfold caliper, this device is an analog method of measuring your body fat that became popular in the 1950s. The device looks similar to the compass you may have used in geometry class. It works by pinching and measuring fat at different sites on your body, then plugging those measurements into a formula to calculate total body fat percentage. 

Before the caliper, people used scales, measuring tape, and BMI. However, none of those methods gave a reliable, accurate picture of a person’s body fat levels, as they failed to consider certain factors.

For example, Dr. Priya Sumithran of the University of Melbourne explains BMI doesn't consider muscle mass in its formula and could suggest that a robust and healthy person is approaching obesity. And for similar reasons, you can't rely solely on the scale to give you an accurate picture of your overall health.

Now in 2023, other devices to measure body fat have hit the market, each with its own advantages and disadvantages. However, a body fat caliper is unique because it’s an affordable at-home method that allows you to calculate your body fat percentage and tells you where on your body you're more likely to store that fat. You can get that information from other tests, but none are as accessible as reading a body fat caliper. 

How To Use a Body Fat Caliper

If you're ready to skip the doctor's appointment and find your body fat percentage alone, the body fat caliper is here to help. Here's how to get started:

What You Need To Begin

Specific items make this process straightforward:

  • A body fat caliper ($10-$30, available online)

  • A pen to mark your measuring sites

  • A formula to match your chosen method or a body fat caliper chart (both are easy to find online)

  • A basic calculator to do the math (if using a formula)

  • Another person to administer the test (recommended but not required)

Skinfold calipers measure abdominal fat

The Methods

Selecting your chosen method is the first step to using a body fat caliper. A quick search online will give you numerous methods you could use, but the difference between them mainly comes down to how many parts of your body you measure and the formula you plug it into at the end. 

It’s also important to note that some methods are better for specific genders and fitness levels, so you should choose a formula that makes the most sense for your body. 

Two standard methods are the Durnin & Wormersley and Jackson/Pollock methods.

Men and women measure the same sites for both of these methods, but the formulas to calculate body fat percentage differ slightly.

The Durnin & Wormersley Method

This method uses the body fat caliper to measure four sites on the body: the bicep, tricep, subscapular (just below the shoulder blade), and suprailiac (just above the hip bone). 

The Jackson/Pollock Method

The Jackson/Pollock Method has three different versions, all deriving from the original, which require seven measurements: triceps, pectoral, abdominal, subscapula, suprailiac, thigh, and midaxillary (under the armpit). The other two versions of this method require fewer measurements and slightly different formulas. 

Measuring Body Fat With a Caliper

Once you’ve picked your method, it’s time to measure. Below are a few tips to keep your measurements consistent and accurate:

  • If possible, take your measurements before eating or working out first thing in the morning. Don’t partake in strength or resistance training beforehand, as your body’s water retention post-workout can affect skin thickness.

  • Take all measurements from one side of your body.

  • Try to avoid alcohol consumption in the days prior to taking your measurements.

How To Read a Caliper

The first time you read a caliper, the process may seem tedious, but it becomes simple with a little practice. 

Before you begin, practice reading a caliper. Pinch a measurement site with your thumb and index finger, pulling the fat away from your skin but leaving room for the caliper to pinch near your fingers. With your other hand (if you’re doing it yourself), use the caliper to pinch the skinfold, closing it around the skinfold only until you hear a click. This built-in function tells you when the caliper has the correct measurement. 

Unfurled measuring tape in front of human standing on scale

Most commonly, calipers have a sliding piece that connects the two “arms” of the device. That scale will feature numbers (like a tiny ruler), showing millimeters on one side and inches on the other. Somewhere on that scale will be a line showing the value you should record. When you pinch the caliper, the scale slides, but the line stays in the same place. You're looking for the number that the line points to once the caliper clicks. 

Many videos and diagrams are available for free online, breaking down how to measure each site. For the sake of length, this article won’t delve into the details of each spot, but in summation, the process involves the following steps:

  1. X marks the spot. Before measuring, take the time to find the correct site and mark it with a writing utensil. 

  2. Make your skinfold. Using a guide for your chosen method, note whether the site you’re measuring requires a horizontal, vertical, or diagonal skinfold. The direction of the skinfold matters, so follow instructions carefully, then make that pinched skinfold with your fingers. For example, when measuring the abdominals, you’ll always measure using a vertical fold next to the belly button. 

  3. Read the body fat caliper. Once you have your skinfold in your fingers, it’s time to bring in the caliper. Place the tips of the caliper on the skinfold and compress it until it clicks, as detailed above. Take note of the measurement, which will be in millimeters and indicated on the caliper. Use your instruction manual to ensure you correctly read the caliper’s measurement.   

  4. Measure your skinfold — again. Most professionals recommend you measure each site three times, then use an average of your three measurements when it’s time to calculate your results. To find the average, add up the three measurements and divide them by three. Write down your measurements, as you’ll use that average for the formula in the next step. 

  5. Calculate your results. Once you’ve measured the required sites, it’s time for some math. As noted above, each method employs a different formula. This may sound intimidating if you’re not a math person, but it just requires plugging numbers into the provided formula. A graphing calculator is recommended, but a basic calculator will also do the job. Make sure you use the right formula for your method and gender. The results of the formula will give you your estimated body fat percentage.

If the formulas seem complicated, there are two other options to get your results: a body fat caliper chart pdf or a body fat caliper calculator. Both are easy to find for free online; follow the instructions and ensure you use the right calculator or chart for your gender and chosen method. 

Women measures back fat with skinfold calipers

Interpreting Results: What Does It Mean? 

Once you have your body fat percentage, it’s time to consider what it means for your health.

The range of healthy body fat percentages depends on your age and gender. For adults ages 20 to 69, the range of body fat percentages considered healthy are as follows:

Women: 16.5 percent to 31.3 percent

Men: 10.5 percent to 25.2 percent

That range is typically further divided into categories like excellent, normal, and average fitness, but all show adequate health. You may increase your health risk if your body fat percentage falls above or below those numbers, depending on your age and other external factors.

Low Body Fat and Aesthetic Goals

A common question from those on a fitness journey is what body fat percentage you need to achieve to have visible abs or a sculpted look.

Unfortunately, this question has no simple answer; it depends on factors like gender, age, and genetics. 

While there is no magic number, visible abs require a lean physique, so you would want to fall on the lower end of the healthy body fat range. For women, that would be at 20 percent body fat or below. For men, it’d be 13 percent and under. 

However, regardless of body fat percentage, it’s vital to note that some people are likelier to get six-pack abs simply because their body stores fat elsewhere or they have a fast metabolism. And while you can take action to boost your metabolism, you can only alter it so much, and you can't control where your body stores fat. These traits mainly come down to genetics.

Ultimately, if you want to increase your chances of having visible abs, more factors are at play than just your body fat percentage. Pay attention to your calorie intake, stay active, and do core exercises to build and tone your abs, so once you shed the fat, your abs are already there beneath it all. 

Doctor measures patient with skinfold calipers

How Accurate is Caliper Body Fat Testing?

Researchers and doctors alike have utilized body fat calipers to gain an understanding of a person’s health for nearly three-quarters of a century, so clearly, there’s merit to their results. However, it’s essential to understand that using a body fat caliper leaves room for human error or inconsistent results. 

Generally, a caliper body fat test has an accuracy level of plus or minus approximately 4 percent. That range is because of the number of variables involved in using and reading a caliper. 

As noted above, you must remain consistent when measuring and reading your body fat caliper. For the most accurate results, you need to measure the same side of your body at the same time of day each time, with similar behaviors prior to measuring. (Don’t work out, and don’t eat, if possible.)

Two of the main variables that leave room for error are the skinfold sites and the technique of the measurer. 

To get the most accurate results, you must measure skinfolds at the right site on the body. This may take some practice, and depending on your chosen method, it may require an extra set of hands. (Some methods require measurements on the backside of your body.)

Technique matters, too, mainly because the measurer must remain consistent with each measurement at each site every time they administer the test. 

Finally, some experts note that the accuracy of your results may vary depending on your body composition and the formula you choose. For example, some maintain that the caliper typically gives lean people a reading that's a few percentage points lower than their actual body fat percentage. Others say specific methods, like the Durnin & Womersley Method, will add a few percentage points to those on the leaner end of the spectrum.

For the most accurate results, do a little research to select the best method for your body.

Doctor measures patient's body fat with skinfold calipers

Body Fat Calipers: A Tool for Everyone

Regardless of your interest in body fat percentage, the body fat caliper is a great tool to add to your health journey. It’s an affordable tool that's relatively simple to use once you’ve gotten the hang of it. 

While the body fat caliper test isn’t an exact science, it doesn’t ignore the concept of muscle mass like the BMI essentially does, and it takes a lot more into the equation (literally) than just your weight or your waist circumference.

Don’t let a new tool and some math intimidate you. Take advantage of its accessibility and add a body fat caliper to your health journey today. 

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