Body Fat Calculator — Know Your Body Fat Percentage In 2024

Body fat is something we all recognize and in some cases obsess over. When trying to obtain our ideal physique, we look to reduce our body fat to make our muscles more visible. When trying to gain weight, we often look to pile as much muscle mass as possible.

However, measuring body fat can often be a time-consuming and expensive process depending on the method you use. Body fat calculators provide a non-invasive, easy-to-perform body fat estimation. 

In this article, we teach you how the body fat calculator works. We also look at its importance when it comes to health and wellness. 

How Does This Body Fat Calculator Work?

This body fat calculator works using scientifically proven formulas to estimate your body composition. The two primary methods used are the U.S. Navy method and the body mass index, or BMI.

By inputting certain body measurements, it works as a sophisticated tool to estimate your body fat percentage. Alongside this, it gives a few other useful readouts. These include your body fat category, lean body mass, and body mass index. 

Input Data

To get started, you’ll need to take some measurements. Once you have done so, you can add these details to the calculator: 

• Gender: Male or female at birth.
• Age: In years.
• Weight: In kilograms or pounds.
• Height: In centimeters or inches.
• Neck measurement: In centimeters or inches.
• Waist measurement: In centimeters or inches.
• Hip measurement: Only for females, in centimeters or inches.

Output Data

Once the calculations are finished, the body fat calculator will give you these measurements: 

• Body fat percentage.
• Body fat category.
• Body fat mass.
• Lean body mass.
• Ideal body fat for a given age.
• Body fat to lose to reach ideal.
• Body fat BMI method.

How Does This Tool Work?

To calculate your body fat percentage, the calculator needs certain body measurements. For males, it needs your neck and waist. For females, it needs your neck, waist, and hips. 

Following this, your BMI will be calculated using your weight and height. This provides a number that will fall into different ranges. Each range tells you if you’re underweight, a normal weight, overweight, or obese.

While it provides a quick and easy estimate, it can’t tell the difference between muscle and fat. Because of this, it may give false readings to certain populations. This is why taking body measurements is vital to provide a more accurate body fat percentage result. 

With this data, the calculations are done using standard formulas. These consider the distribution of muscle, bone, and fat throughout your body. 

They’re measured using the United States customary measurement system, or USC units. These are inches, feet, and pounds. 

Body fat percentage (BFP) formula for males:

USC Units:

BFP = 86.010×log10(abdomen-neck) – 70.041×log10(height) + 36.76

SI, Metric Units:

BFP = (495/(1.0324 – 0.19077×log10(waist-neck) + 0.15456×log10(height)) – 450

Body fat percentage (BFP) formula for females:

USC Units:

BFP = 163.205×log10(waist+hip-neck) – 97.684×(log10(height)) – 78.387

SI, Metric Units:

BFP = 495/(1.29579 – 0.35004×log₁₀(waist+hip-neck) + 0.22100×log₁₀(height)) – 450

The equations shown above provide estimates. This is because they are designed for general use rather than specific individuals. 

Physical measuring tools provide a more accurate body fat measurement using methods such as bioelectric impedance analysis and hydrostatic weighing.

Bioelectrical impedance analysis works by running small electrical currents through the body. With the electrical conductivity being different between body tissues, this can determine the percentage of body fat. While it’s more accurate than a calculator, it comes at the cost of convenience.

Hydrostatic weighing works by measuring body density in the air compared to the water. When the Archimedes principle is applied, this allows you to see the difference between body components, including fat. Like bioelectric impedance analysis, it’s more accurate but much more time-consuming.

Fat mass (FM) formula:

FM = BF × Weight

Lean Mass (LM) formula:

LM = Weight – FM

BMI Method

When measuring body fat percentage, or BFP, you need to use your BMI and age. You input these into different equations depending on your gender and age. When done correctly, they should give you a body fat percentage estimation. 

To calculate your BFP, use the formulas below: 

Adult males: BFP = 1.20 × BMI + 0.23 × Age – 16.2

Adult females: BFP = 1.20 × BMI + 0.23 × Age – 5.4

Boys: BFP = 1.51 × BMI – 0.70 × Age – 2.2

Girls: BFP = 1.51 × BMI – 0.70 × Age + 1.4

The output from these formulas provides you with an estimate of your BFP. This can give you an indication of your general health when comparing the value to the reference ranges.

As mentioned previously, BMI can’t distinguish between muscle and fat. Therefore, the reading may show a high BMI even though you have a low body fat percentage. 

This is one of the possible disadvantages of using BMI as a health estimation. It can be used as more of a categorization for body index scales rather than a specific value.

If a higher body fat percentage is given, you should be aware of the potential risks. With a regular health check-up, you can learn more about the risks and potential steps you can take to limit them.

Body Fat Categorization

The benchmark for comparisons is broken down into essential fat, athletes, fitness, average, and obese categories:

Description	Females	Males
Essential fat	10-13%	2-5%
Athletes	14-20%	6-13%
Fitness	21-24%	14-17%
Average	25-31%	18-24%
Obese	32+%	25+%

For a more detailed look at what your ideal body fat could look like per age, you can reference the Jackson and Pollock Ideal Body Fat Percentages:

Age	Females	Males
20	17.7%	8.5%
25	18.4%	10.5%
30	19.3%	12.7%
35	21.5%	13.7%
40	22.2%	15.3%
45	22.9%	16.4%
50	25.2%	18.9%
55	26.3%	20.9%

Why Our Body Fat Calculator Is Reliable

Body fat calculators need to be built on foundational scientific methods that have been well-researched. This ensures an accurate estimation that’s been created from informed information. That’s exactly what you get with our body fat calculator.

The U.S. Navy’s body fat formula is used to inform the main calculations. It’s something that’s been used throughout research for decades due to its excellent reliability.

What makes it great is the fact that you can estimate body fat using simple body measurements. Alongside this, it takes factors such as gender differences and age into account. These are things that may influence the overall results.

With this, differences in fat distribution can be analyzed to give a much more accurate output. 

Our body fat calculator stands out from the rest because it’s built on a foundation of well-researched and widely accepted scientific methods. Alongside this, it cross-references the results with the BMI method of measuring health status. Doing this ensures the output results are consistent with health standards 

The tables above provide some useful comparisons that allow you to better manage your health status. Using these can help to inform motivations to find your ideal body fat percentage.

When we put these things together, we have a handy estimation tool that’s easy to use for all ability levels. The simplified process means that all you need is a tape measure and yourself. 

Risks Of Overweight And Obesity

When comparing your body fat results to the reference ranges, there are certain risks to bear in mind. These are some of the main ones to consider: 

• Type 2 Diabetes — This occurs when your body is unable to properly regulate and use sugar as fuel. Being overweight or obese may cause your body to become resistant to the hormone insulin or not produce enough. Type 2 diabetes can cause chronic blood sugar imbalance, requiring medical intervention. 
• Cardiovascular Disease — This relates to chronic cardiovascular conditions such as heart disease and stroke. Being overweight or obese can lead to high blood pressure and cholesterol, both of which are big risk factors. In 2021, cardiovascular disease accounted for 20.5 million deaths, which is almost one-third of total deaths globally.
• Fatty Liver Disease — Caused by a build-up of excess fat in the liver. The two main types are non-alcoholic fatty liver disease and alcoholic fatty liver disease. If left to progress, this can cause chronic inflammation and cirrhosis, or permanent scarring. 
• Metabolic Syndrome — This refers to a cluster of different medical conditions. Examples include high blood pressure, high blood sugar, excess cholesterol, and excess abdominal fat. Put together, these increase the risk of chronic conditions such as diabetes, stroke, and heart disease. 
• Gut Imbalance — The gut microbiome refers to a collection of microbes in our gut that support energy production, immune function, and digestion. If this becomes disrupted, it may lead to gut issues that require medical intervention. This can cause several health issues including irritable bowel syndrome, metabolic disease, and mental health issues. 
• Reproductive Health Conditions — Reproductive system issues can affect both men and women. These include infertility, pregnancy, and childbirth complications, and irregular menstrual cycles. 
• Mental Health Conditions — Several mental health issues can be linked to the physical problems of being overweight or obese. Managing stress caused due to discrimination and stigma can have wide-ranging effects. These include anxiety, depression, low self-esteem, and body dissatisfaction. 
• Sleep Apnea And Respiratory Problems — Being overweight or obese can lead to respiratory issues or make existing ones worse. Examples include breathing difficulties or periods where breathing stops when sleeping. Over time, this can lead to chronic daytime fatigue and an increased risk of heart disease. 
• Joint Pain — As we move around and exercise, our joints need to support our body structure. Excess body weight can cause increased joint pressure, especially in the lower back, hips, and knees. This can lead to joint pain, soreness, and chronic degenerative conditions such as osteoarthritis. 

How To Reduce Body Fat

Reducing body fat requires a structured, long-term approach. Following the tips below can help you to adopt a holistic approach to long-term weight management. 

Go Slow

When losing weight, most people tend to think that a faster approach will lead to quicker weight loss. While this may be the case initially, this doesn’t tend to be the case long-term. 

Losing weight requires gradual, systematic changes. Phrases like “Tomorrow, I’ll eat well, work out, and go to bed early” fail to address the long-term mindset needed. These kinds of habits require many steps and should slowly be built over time. 

Juggling our social lifestyles and professional responsibilities requires a structured approach. Adding healthier habits to this means we need to adapt each lifestyle component to suit one another. 

Rather than trying to reinvent the wheel straight away, start with small changes that can gradually be built in. Set small, manageable goals that can be built on before progressing to the bigger ones. Focusing on one manageable healthy habit at a time has been shown to lead to better long-term success. 

For example, adding more fruits and vegetables is an easy, achievable goal that can be built on when accomplished. It’s specific, measurable, achievable, realistic, and time-bound. This aligns with the smart goal-setting principle. 

When you have this, think about what it will achieve to accomplish the goal. Could this be planning a weekly shopping trip so that there is always fruit in the house? Could this also mean ensuring the freezer is always well stocked on frozen vegetables so you have stocks in reserve?

Working on these manageable, realistic habit changes helps to build a solid foundation to build on. Setting unrealistic goals and forcing yourself to adopt habits that you don’t enjoy is unsustainable. 

Prioritize Whole Foods

Whole foods are minimally processed which means they maintain their natural state. Because of this, they’re full of vitamins, minerals, and fiber. These perform several vital functions in the body including energy production, immune function, and hormone regulation. 

Good examples of whole foods include fruits, vegetables, legumes, nuts, and seeds. Eating more whole foods rich in fiber and protein helps improve satiety, which refers to the state of feeling full. 

When consumed in the right amounts, this can prevent snacking and overeating. Over a longer-term period, this can help maintain a calorie deficit which is a key factor for weight loss. 

Alongside this, whole foods tend to be lower in sugar and unhealthy fats. These can help to decrease sugar cravings and balance blood sugar levels. To prioritize whole foods, a practical tip is to eat the rainbow. This means adding a colored whole food to a meal or snack. 

Manage Stress

When thinking about health, physical health is often seen as the most vital component. However, when we view health holistically, we start to see the links between our mental health and physical aspects. Managing this effectively can improve aspects of our physical health which includes our body composition.

Chronic stress elevates the level of cortisol, a stress regulation hormone that constantly fluctuates in our body. While a normal level of cortisol is needed, chronically elevated levels can negatively affect metabolism and lead to weight gain.

Therefore, practicing self-care routines and stress-relieving activities should form a vital part of a weight maintenance routine. For example, a lack of sleep can disturb hormonal balance which can decrease metabolic rate. This is associated with weight gain and possible mental health issues over a longer period.

Increase Cardio

When performing cardio exercise, the body requires more energy to sustain the correct movement patterns. In the immediate period following, it needs more energy to perform recovery processes such as tissue repair and energy production. 

This increase in energy expenditure can help to maintain energy balance. As a key contributor to weight gain, this can help to reduce body fat when done using enough volume.

Cardio exercise doesn’t have to mean using the treadmill or elliptical for hours on end. You can also use inventive and fun ways to get your heart rate up and burn more energy. This could include taking a walk in the park or signing up for a fun dance class with your friends.

Try Strength Training

Alongside cardio training, strength training can form part of a well-organized exercise routine. When done correctly, strength training helps to build muscle mass. Muscle uses more energy than fat, meaning that a higher muscle mass increases your metabolic rate.

When looking to reduce body fat, strength training can form a vital part of your training routine. While a fancy gym is great, you can also use a mat and a suitable floor space at home. The main point is to be consistent with your strength training and find something that you enjoy doing.

When building muscle mass, ensure you follow the basic principles of resistance training. Volume is a key determinant, which refers to the amount of work performed. If in doubt, enlist the help of a qualified health professional such as a personal trainer. 

Create A Caloric Deficit

When it comes to fat loss, energy balance is a key factor. This refers to the balance between the energy you take in and the energy you use or burn.

A calorie deficit is needed for successful fat loss. This means that you burn more calories or energy than you consume. This can be accomplished through exercise, diet, or a combination of both.

Generally speaking, a calorie deficit of approximately 500–1000 calories per day is recommended. This should be done for 8–12 weeks, allowing a break before starting again. This helps to provide long-term, sustainable weight loss of around 1–2 pounds per week. 

When creating a calorie deficit, it’s important not to overly restrict yourself. We need a certain amount of calories and essential body fat to survive. Too much restriction can lead to malnutrition and possible health issues that negatively contribute to overall health status. 

Use your basal metabolic rate or BMR to estimate the amount of calories your body needs at rest. Adding a physical activity level gives you your baseline maintenance calorie intake which you can base your deficit on.

Remember that overly restrictive diets increase the chances of disordered eating habits and reduce the possibility of long-term success. When creating a calorie deficit, it’s important to use a gradual approach that suits your circumstances. This allows healthy weight loss and avoids the possibility of crash dieting or unhealthy rebounds.

The Bottom Line

Making positive health changes by reducing body fat and changing lifestyle habits doesn’t happen overnight. It takes time and patience to use a structured approach built on solid scientific principles. 

The body fat calculator provides a handy estimation of your current body fat levels using basic physiological characteristics. It uses foundational scientific principles to give you a trustworthy estimate that can be used to improve health. Use it alongside the tips above to improve your body fat levels and promote long-term, sustainable lifestyle changes.

Frequently Asked Questions