How to measure your body fat percentage yourself!

Along with body weight and the weight you can bench press, body fat percentage is one of the most sought-after numbers you’ll encounter in the gym. Besides the legendary status of body fat percentage, it’s also one of the most decisive figures when it comes to your physical progress. After all, gaining 10 kilos in body weight is not very impressive if it comes with a 10% increase in body fat. The opposite is also true, as we all know someone who has lost a lot of weight but no longer has an ounce of muscle left. But that body fat percentage, how do you actually calculate it yourself? That’s what we’re going to help you with today!

WARNING: Body fat percentage is not foolproof!

There are countless ways to measure body fat percentage, and some of the most advanced methods involve submerging your entire body in a water bath or undergoing a full-body DEXA scan. Although these methods are the gold standard for measuring body fat percentage, even they are not perfect. There can always be a small margin of error, meaning you will always get at best a very good estimate. So, your body fat percentage is not as precise as your body weight.

Let it be clear that the methods described in this article give you a good indication of your body fat percentage, but there will always be a margin of error of a few percent. Measure yourself a few times in a row, and you’ll likely end up with 3 different results. A trained coach who performs skinfold measurements daily will, of course, achieve a better result than you would when using the caliper for the first time. So, unless you want to spend a fortune on the most accurate measurement, the estimates from this article are your best choice!

The different methods

In this article, we won’t go over all the possible measurement methods available on the market. Why not? Because for the majority, it doesn’t add much value. Today, we’re going to cover the best methods with which you can measure your body fat percentage yourself!

BMI

The first and simplest method to calculate your body fat percentage is by using your BMI. BMI stands for Body Mass Index, an index that shows the ratio between your height and weight. For untrained people, this is a good measure to determine whether someone is overweight, underweight, or has an ideal weight for their height. The BMI has received a lot of criticism because it’s not always accurate, and that’s true. Especially if you’re reading this, you probably belong to a group of people who do a lot of strength training and therefore have more muscle mass than the average person. As a result, many people are considered overweight according to the Body Mass Index and are advised to lose weight, even though they can count their abs.

Not the most accurate representation, then... However, researchers [1] have found a strong relationship between BMI and body fat percentage. For a large part of the population, it is a good guideline to follow. The researchers did admit that this method has its limitations, especially for people who are very light or very heavy, or, as mentioned earlier, bodybuilders. That being said, for untrained individuals or beginners in the gym, your BMI can give a good indication of your body fat percentage. You don’t need much information, and no special measuring equipment is required. All you need is a scale! This makes it a very accessible method to still get an estimate of your body fat percentage.

Calculate your body fat percentage below using your BMI.

The Measuring Tape

Using your BMI has clear limitations for strength athletes who have been training for a longer time, so what other options are there? Meet the United States Navy! The U.S. military is an organisation where health and well-being are important for the functioning of its employees. The link between body weight, particularly overweight, was quickly made. For this reason, in 1984, the U.S. Navy developed body fat calculations at their research centres based on underwater weighing. They started comparing measurements taken with a measuring tape to the results of much more reliable methods and found a surprising amount of similarities between the two! This is how the U.S. Navy Body Fat Calculator was created. This method involves entering your height, neck circumference, and waist circumference into a calculator, which then gives you your body fat percentage. For women, hip circumference is added due to the different fat distribution compared to men.

Let’s be clear: no, this method is not going to give you the most accurate representation of your body fat percentage. With only two circumferences, you can’t say everything about someone’s body fat percentage. However, it has been shown to provide a very good estimate, and its consistency is excellent. A shortcoming of skinfold measurements is that the precision of the measurements is crucial. When measuring circumference, the chance of error is much smaller. Especially a tape measure that tightens itself is a great addition to guarantee the quality of your measurements.

The Bio-Impedance Measurement

Another well-known method to calculate your body fat percentage is the bio-impedance meter. Commonly referred to as a scale that shows not only your weight but also your body fat percentage. A great and simple method to find out your body fat percentage. Unfortunately, there is one drawback: that convenience comes at a high cost, namely accuracy! A bio-impedance meter can either be found in a scale or a device you hold with both hands. Both work in the same way: they send a small electric current through your body and measure the time it takes to return to the other side (your leg or arm, respectively). The idea is that the body is made up of 70% water, which allows electricity to pass through easily.

Fat contains much less water, making it harder for electricity to pass through. The more fat you have, the longer it takes for the electric current to return, resulting in a higher body fat percentage.

The drawbacks:
The theory behind this is great, but unfortunately, it doesn’t work as perfectly in practice. First, the electric current will always take the path of least resistance. If it has the option to travel through water instead of fat, the fat tissue will be easily bypassed. Additionally, bio-impedance meters only have two electrodes: either two on the feet in the case of a scale or two for your hands. It goes without saying that in both methods, one half of your body is completely ignored. As a result, at best, it provides a very incomplete picture.

Lastly, the accuracy of the measurement is generally poor. Hydration levels alone can have a huge impact on the results. Try measuring yourself before and after a tough interval cardio session for fun. The scale will likely tell you that your body fat percentage has increased by a few percent. How is this possible? You’ve lost a lot of water, making it harder for the electric current to pass through your body, as there is less water present. This leads to relatively more resistance in the body, which translates into a higher body fat percentage.

So, while the bio-impedance measurement may be the simplest method, and since it’s all automated, it seems very ‘high-tech’, this comes at the cost of poor accuracy. Therefore, we recommend looking at the other methods.

The Skinfold Measurement

Finally, we come to the most well-known method: the skinfold measurement. Most people have heard of it, and while it might seem like there’s only one type of skinfold measurement, that’s not the case. There are numerous methods, each estimating your body fat percentage based on different points, which of course results in varying outcomes. But first, let’s go back to basics: what is a skinfold measurement? It’s quite simple, really. Using a caliper, you pinch the skin and fat layer at specific points on your body and measure the thickness. It’s important to have a consistent measurement, meaning you should do it exactly the same way each time. Some recommend pinching a piece of skin about 2-3 cm thick and measuring that section.

Meanwhile, others try to grab as much fat/skin as possible and measure that. Since there is no absolute truth when it comes to skinfold measurements, you can choose either method. The key is to always do it the same way. Sure, your body fat percentage will vary slightly with both methods, but skinfold measurements aren’t super accurate to begin with. So, you pinch some skin and fat, measure the thickness, and then what? You input these values—usually expressed in millimetres—into a calculator along with your body weight, gender, and age. This gives you an estimate of your body fat percentage, which you can use to track your progress over time.

Looking for a good skinfold caliper? You can choose between a standard body fat meter or a handy digital version! Which method do we use? The most well-known skinfold calculators are the Jackson/Pollock, Parrillo, and Durnin/Womersley methods. Which one is the most accurate remains a debatable point, but the 4-point Durnin/Womersley method typically gives an estimate that isn’t unrealistically low and is the most accurate for a large part of the population. However, here’s the downside: you can’t measure any of these points yourself except for one! For that reason, we recommend the 3-point Jackson/Pollock method. For men, this involves measuring the chest, abdomen, and thigh. For women, it’s the triceps, suprailiac (side of the abdomen), and thigh. These are points that can generally be measured on your own, except perhaps the triceps. For this, ladies can ask for help from a friend/family member/training partner, or you can try extending your arm straight ahead and pinching the skinfold yourself. With this 3-point measurement, you’ll get an acceptable estimate of your body fat percentage, and during a fat-loss diet, it’s a good method to track your progress (bi-)weekly.

Conclusion

Measuring your body fat percentage can be a valuable tool to monitor your physical progress, but it’s important to realise that no method is completely accurate. Whether you choose the easy-to-calculate BMI, the accessible US Navy method, the modern but less accurate bio-impedance measurement, or the traditional skinfold measurement—each method has its own pros and cons. The key lies in consistency: choose the method that works best for you and measure regularly in the same way to track your progress. Ultimately, your body fat percentage is just a number; what matters most is how you feel and how your body functions. Stay focused on your overall health and well-being, and let these measurement methods support you on your journey to achieving your fitness goals.