Estimate your Body Fat Percentage, calculate BF for men and women

The composition of human body

More than 98% of the human body is composed of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Potassium, sulfur, sodium, chlorine, and magnesium are responsible for almost another 1%. These are the 11 most important, so called non-trace, elements. Regarding the molecules, the most common molecule in the human body is of course water, which takes about 65% of mass, followed by proteins and lipids. Other molecules which have a decent percent of mass are hydroxyapatite, carbohydrates and nucleic acids.

What is body fat?

It is actually adipose tissue; its main function is to store energy in the form of lipids, but it cushions and insulates your body, too. Your body stores two types of fat: essential and storage body fat. The former is necessary to support life and reproductive functions. Essential body fat is substantially higher for women because of childbearing and hormonal functions. Storage body fat is the mass of additional accumulated fat. It does not mean that this type of body fat is unnecessary, though - part of it protects your abdomen and internal organs.

How to calculate body fat?

You can estimate your body fat with our body fat percentage calculator. Remember that no calculator, however complicated, can replace a visit in a doctor's office. You should treat this result as a rough estimate; it can only tell you if your body fat percentage is drastically too high, but there's no reason to panic if the result differ slightly from the recommended value.

To calculate the body fat percentage, you need to take the following measurements:

  • Weight: simply weigh yourself. You will get the most accurate result weighing yourself in the morning, before breakfast, and without clothes on.
  • Waist: your waist is the narrowest part of your torso. The measuring tape you bring around your waist should sit tightly, but it shouldn't "dig" into your skin. Don't pull your stomach in, either.
  • Forearm: the forearm circumference is only needed to calculate the body fat of women. Put your tape around the thickest part of your forearm (close to your elbow).
  • Wrist: wrap a measuring tape around your wrist in the fullest part. Again, this measurement is not required for men.
  • Hip: you measure your hips it the widest point below your waist. Remember to remove your clothing and to keep your feet together so that the measurement is as accurate as possible. Men don't need this measurement either for calculating the body fat percentage.

Once you have taken all of the measurements, you can input them all into the body fat calculator. If you are interested how it works, here are the formulas we use:

lean body mass (men) = (weight * 1.082) + 94.42 - Waist * 4.15

lean body mass (women) = (weight * 0.732) + 8.987 + wrist / 3.140 - waist * 0.157 - hip * 0.249 + forearm * 0.434

body fat weight = weight - lean body mass

body fat percentage (BFP) = body fat weight / weight

Both equations for lean body mass use weight in pounds and all other measurements in inches. If you are using other units, you can transform the formulas accordingly.

Is my body fat percentage normal?

Once you calculated your body fat percentage, you should compare it with the recommended values. The list below comes from the American Council on Exercise and shows the average percentages in specified groups.

  • Essential fat: 10–13% (women), 2–5% (men)
  • Athletes: 14–20% (women), 6–13% (men)
  • Fitness: 21–24% (women), 14-17% (men)
  • Average: 25–31% (women), 18–24% (men)
  • Obese: 32%+ (women), 25%+ (men)

This data means that if your body fat percentage is lower than 31% for women and 24% for men, you are in the average range and you have nothing to worry about. Higher levels of body fat may be dangerous for you.

The chart below shows the average body fat percentages of Americans from samples between 1999–2004. It is taken from the National Health and Nutrition Examination Survey in the United States.

mean body fat chart

Why should I control my body fat?

You need some body fat to regulate the production of hormones. An excessive percentage of body fat, however, can cause multiple health problems, such as:

  • Heart diseases: obesity and high levels of body fat can lead to high blood pressure and high levels of bad cholesterol, which are also risk factors for heart diseases. In extreme cases, they can lead to strokes, the third most common cause of death in the United States.
  • Male hormones problems: high body fat level in a woman's body can lead to an excessive production of male hormones, causing facial hair growth and acne.
  • Diabetes: high body fat can lead to type 2 diabetes. There's a strong correlation between diabetes and being overweight; people most at risk for developing type 2 diabetes are those who have a high body mass index (BMI) and a high body fat percentage.
  • Pregnancy complications: Women with high body fat levels are more likely to give birth prematurely or have children with health problems, including obesity. They are also more likely to need a Cesarean delivery.

Alternative methods of measuring body fat

If you type "how to calculate body fat" into your search engine, you will discover that there are multiple methods for measuring the body fat percentage. In fact, there are even multiple different formulas used in various calculators. The list below gives you some alternative methods.

  • Underwater weighing: fat cells in humans have a density of 0.9 kilograms per liter. The lean body mass has a higher density - 1.1 kg per liter. Knowing this difference, it is possible to determine the density of the whole body by submerging it in water. After making some corrections for air in lungs, you can calculate the percentage of body fat with only a small uncertainty.
  • Skinfold method: it is a method, in which you pinch your skin in several standardized places with calipers and measure the thickness of the fat layer. It requires from three to seven measurements. The drawback of this method is that it only measures the adipose tissue layer directly below the skin, and doesn't take into account any internal body fat.
  • From BMI: there are some formulas that allow body fat percentage to be calculated directly from the BMI. They are not really accurate, though, as the amount of body fat for two people with the same BMI might be completely different.
  • Ultrasound: it can be used to measure tissue structure and hence the amount of adipose tissue directly below the skin.

Body fat percentage versus BMI

Your BMI is your body mass index. This number is different from your body fat percentage because it simply tells you if you’re underweight, normal weight, overweight, or obese. It cannot tell you how much fat is on your body.

While useful in some situations and easy to calculate, your BMI may not be a very reliable indicator of your overall health. If you’re an athlete, for example, you may have a low body fat percentage, but due to all of your muscle, you may have a high BMI. BMI doesn’t take into account other important factors.

Is fat so bad?

Reading all that things you may start to think; "fat is bad and it would be the best to have non of it at all." But is that really true? Let checkout some below examples.

Andreas Münzer was an Austrian professional bodybuilder. In his preparation and training he used multiple ergogenic acids, steroids, diuretics. He was known for his extremely low body fat levels. Unfortunately, his drug taking lead to complications, and he developed upper gastrointestinal track bleeding, which caused his death, because he had no fat to cope with the medical stress after the surgery.

However, no body fat happens not only to bodybuilders. Lizzie Velásquez is a famous American motivational speaker and YouTuber. She suffers from extremely rare congenital disease called Marfanoid–progeroid–lipodystrophy syndrome. One of its symptoms is preventing body from accumulating fat tissue and gaining weight, what causes that such patients have zero percent of body fat. She has never weighed more than 29 kg and is required to eat about 8000 calories daily!

As you can see, fat is not all bad but excess fat is bad!

How to Reduce Body Fat

Now that you know your body fat percentage, are you inspired to reduce your numbers? The method is a simple equation: burn more calories than you eat. But, that doesn't mean that the process is easy. Reducing body fat means making changes in all areas of your life, not just in the way you eat and exercise.

Reducing body fat should not be the goal for everyone. If you fall into the essential fat or even the athlete category, you may consider gaining weight and should speak with your healthcare professional before making a decision. Also, know that these numbers don't apply to pregnant women — you should not try to lose weight during pregnancy. You may also want to speak to your healthcare provider if you are trying to lose weight while on medications or during cancer treatment to make sure that it is safe to do so.

These are areas you may want to focus on if reducing fat is appropriate for you:

Your Diet

How much you eat is a huge factor in losing or gaining body fat. You can always follow a popular diet, but fad diets generally don't work. What does work is to make small changes like:

  • Reduce your portion sizes.
  • Eat smaller meals more frequently throughout the day and avoid skipping breakfast.
  • Eat lots of fruits and vegetables to fill you up and give you the nutrients you need.
  • Eat more fiber. Fiber fills you up so that you don't have room for less healthy foods.
  • Avoid sugary drinks and junk food.
  • Limit how much alcohol you drink.

Your Cardiovascular Fitness Program

Cardiovascular exercise is an important part of any fat loss program, but you want to make sure you do the right kind of cardio. Make sure you're including some high-intensity interval training in your program, up to two to three times per week. You should also incorporate moderate and easy workouts as well.

Your Strength Training Program

People often focus on cardio for losing weight, but adding more muscle will really help you burn more fat. Muscle is more metabolically active than fat so, the more you have, the more calories you burn all day long. Just a couple times a week is all you need to add lean muscle tissue and burn more fat.

Lifestyle Factors

Watching your stress levels and getting enough sleep are the keys to keeping your weight in check since stress hormones can contribute to weight gain. Taking care of yourself will make it easier to maintain the energy needed to complete key workouts and will help you to stay motivated to shop for and prepare nutritious foods. 

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