Lean Body Mass Calculator

lean body mass calculator

It’s important to know how to use a lean body mass calculator, and body fat calculator to work out your lean body tissue and fat levels.  You can then continue to track them to ensure that you are losing fat, and not lean body mass, when following a diet and training program.

If you are losing lean body mass, and not fat, then you will end up with the dreaded skinny fat body, and you will be less healthy than when you started.  This can occur if your nutrition plan is not worked out properly, and / or you are doing too much steady rate cardio, and not enough strength training, leading to muscle wasting.

Nobody wants to be skinny fat, better to be lean and strong!

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Over training is a trap that fitness fanatics can easily fall into as well, which will lead to muscle waste, and therefore a decline in lean body mass.

Methods to calculate lean body mass

Bearing in mind that the body structures of males and females are different, there are four main methods used by a lean body mass calculator to estimate lean body mass.  These formulas are as follow;

Boer Formula:

For Men:

0.407 × weight[kg] + 0.267 × height[cm] – 19.2

For Women:

0.252 × weight[kg] + 0.473 × height[cm] – 48.3

James Formula:

For Men:

1.1 × weight[kg] – 128 × ( weight[kg] / height[cm] ) 2

For Women:

1.07 × weight[kg] – 148 × ( weight[kg] / height[cm] ) 2

Hume Formula:

For Men:

0.32810 × weight[kg] + 0.33929 × height[cm] – 29.5336

For Women:

0.29569 × weight[kg] + 0.41813 × height[cm] – 43.2933

Peters Formula:

The peters equation is used to calclate LBM of children (up to 13-14 years old) and this equation is based on an estimated extracellular volume (eECV) as given:

eECV = 0.0215·W0.6469·H0.7236

eLBM = 3.8·eECV

You can select any of these formulas in the lean body mass calculator below;

The most accurate way to calculate your lean body mass however, is to first measure and calculate your body fat percentage.

Once you know your body fat percentage, it’s easy to calculate lean body mass accurately using the following simple formula;

Body fat % divided by 100 x total body weight = answer – total body weight = lean body mass

Eg; If I weigh 69kg with 18% body fat the formula would be;

18 / 100 x 69 = 12.42 – 69 = 56.58kg lean body mass.

The important key to obtaining an accurate lean body mass measurement is to first have an accurate body fat measurement.

This has all been included in the lean body mass calculator and body fat percentage calculator below.

The body fat percentage calculator enables you to select any of the nine methods of calculating body fat, therefore you will be able to obtain accurate data, based on the measurement methods readily available to you.

Methods of measuring body fat percentage

So, to calculate your body fat percentage and therefore how lean are you, the following methods, as included in the calculator above, will help you to get the result.

Also, following the description of these methods, you will find a diagram to help you with the skinfold or points to be measured on the body, as referred to in these methods.

(YMCA) Method

This method uses the formula developed by the YMCA that aims to evaluate the body fat of an individual, although this approach is not reliable as a water displacement test. This methodology only works within 1-3% accuracy for most people.

The steps to apply this test are using a tape measure to get the measurements of your waist. The waist is located between the belly button and below the rib cage. After having the waist measurement, the formula will consider the gender and current weight to generate the body fat result.

Modified YMCA Method

The difference between the body fat calculator YMCA and the modified YMCA Method is that in this method five different measurements are taken for the female group such as Forearm circumference, hips, waist, weight, and wrist. All five measurements are necessary to calculate the body fat for a female group, while for the male group the measures are only for waist and weight, the same as the body fat calculator YMCA.

This formula is more accurate for women with a pear body shape due to the measurements taken around the hips, while for man it is consistent with the body fat calculator YMCA.

Covert Bailey Formula

This is considered one of the most recent formulas to measure body fat and is done in imperial measurements. It consists in taking the size of four different parts of your body;

For a female group the measures are for the calf, hips, thigh and wrist, while for the male group the same measurements except for the calf which instead is the forearm circumference.

Jackson/Pollock 7 Calliper Formula

This method for measuring body fat was created by Dr Jackson and Dr Pollock as its name indicates. This formula measures seven parts of the subcutaneous fat of the body. The same locations for the measurements apply for both men and women.

For taking these measurements in the body you are going to need a skinfold calliper and use it in the right side of the body, pinching the middle of the skin. Experts recommend taking the measurements twice for increased accuracy of the results. If there are huge variations between the two results, then take a third measurement.

The seven locations of the body for the measurements are:  Abdominal, Chest, Midaxillary, Subscapular, Suprailiac, Triceps and Thighs

Jackson/Pollock 3 Calliper Formula

As mentioned in the previous formula this formula was created by Dr Jackson and Dr Pollock. This method measures three points of body, recommended to be the right side. The difference here is that the measurements for the group of women are different of the group of men.

For men the skinfold measurements are taken for abdomen, chest and thigh; While for the female gender measurements are taken for suprailiac crest, thigh and triceps.

For the best results it is important to take the measurement twice, if these measures are not consistent is recommend doing it for the third time for greater accuracy.

Jackson and Pollock 4 Calliper Formula

This formula provides the body fat percentage measured with only four skinfold measurements, a little simpler than the Jackson and Pollock 7 calliper formula and more accurate than the Jackson and Pollock 3 calliper formula.

The four points of measurement for the skinfold are the same for the group of women and men.

It is recommended to measure the right part of the body and doing each measurement twice for accuracy. Again, do a third measurement if your two results vary  too widely.

The four points are Abdominal, Suprailiac, thigh and triceps.

Parrillo Calliper Formula

This formula helps to provide a body fat percentage using a calliper as a tool and measures nine skinfolds points of the body for both men and women. The fact that this method does not differentiate between both genders makes it less accurate than other methods that do differentiate between genders.

The nine skinfold measurements are taken from the Abdominal, Bicep, Calf, Chest, Lower Back, Subscapular, Suprailiac, Tights and Triceps.

Durnin / Womersley Calliper Formula

This method for measuring body fat was created by Durbin and Womersley. This formula measures four skinfold points in the body, which are the same for the group of female and male including all the age ranges. Therefore, when this method is compared with other methods, the body fat percentage formula is not as accurate.

This formula works better on the average person, meanwhile for athletes or fit people it’s not the best one due to the core fundamental in the formula.

The skinfold measurements are taken for the Bicep, Subscapular, Suprailiac and Triceps.

Navy Tape Measure Formula

This method of measuring body fat is, as the name suggests, used in the U.S navy to estimate your body fat as one of the filters required to join the military service.

The tool for taking the dimension required for the result of the body fat % is a tape measure for getting the dimensions of the hip, neck, and waist. Those are combined with the gender and height.

Body Fat Measurement Locations

body fat measurement locations chart

Ideal body fat percentage chart

*From the American Council on Exercise




Essential fat















Understanding Lean Body Mass

The medical definition of lean body  mass according to William C. Shiel Jr., MD, FACP, FACR is “the mass of the body minus the fat”

Your lean body mass is basically all of your body composition including a small percentage of essential body fat, less any other body fat.  The essential body fat for men is 3% – 4% of total body mass in men and 5% - 7% of total body mass in women.

Lean body mass weighs more than fat. In fact, muscles are 79% of water meanwhile fat is only 5-10% water composition. Therefore, lean body mass is eight times more dense than the corresponding amount of fat.

For example, having two people of the same age and height, one of them can show a normal weight and have excess of fat, meanwhile, the other one can be heavier more than they should be according to the BMI tables, and without taking the body fat measurements of both, you can’t know their lean body mass, and therefore whether they are a “healthy” body composition or not.

Why is lean body mass different to body fat mass?

The reason for this is that lean body mass weighs much more than the fat, and it is the best indicator for determining when a person is within the range of healthy or unhealthy (obesity or malnourished), although the lean body mass varies within an average person, an athlete and between genders.

Two people of the same sex, height and body weight can look completely different, due to their different body composition.

For example, lean body mass for an athlete is lower than the average person. Men have less body fat than women as men tend to have more muscle mass than women and females hold more fat due to the way the body works for the role of the women to become a mum.

People who are leaner have a higher metabolic rate. This means, people with less body fat have a quick metabolism, therefore, they burn more calories.

Lean body tissue takes up less space than body fat tissue, so if you want to be smaller or “leaner” it makes sense to increase lean body tissue, thereby speeding up your metabolism and losing excess body fat.

Why is lean body mass different to muscle mass?

So, as we’ve outlined above, lean body mass is essentially the total weight of your body minus the excess or non-essential fat mass.

Muscle mass is therefore a part of your lean body mass. 

Given muscle is also 80% water, the amount of fluid you have in your body throughout the day will cause muscle mass to fluctuate, as therefore does your lean body mass.

A gain in lean body mass is therefore not always a gain in muscle mass.

Just drank 5 glasses of water, my lean muscle gains are off the charts!

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When people talk about ‘lean muscle’ it’s a bit misleading.  What they really should be referring to is lean body mass.

Skeletal muscles are the muscles which are developed through resistance training. It’s difficult to calculate accurately how much of a lean body mass gain is due to an increase in skeletal muscle, particularly given the fluctuation of water content within muscle, and lean body mass generally.

The In Body direct segmental multi frequency bioelectrical impedance analysis will give you a result that separates your skeletal muscle mass from your lean body mass. So, if you have access to one of these machines to monitor your body composition, then use the technology!

For the rest of us, it’s best to focus on what you can measure most accurately, so track your body fat and lean body mass.  From these you will get a good measure of how your body composition is changing.

You know the how and why of using a lean body mass calculator

I know this article will help you to find how lean your body mass is, and percentage of body fat you have, to help you stay on track to a fitter, healthier, leaner body.

Now it’s up to you to stay focused, be disciplined with your training and diet, and achieve your fitter, leaner, healthier physique!

These articles will help you achieve your lean body mass goals;

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9shares 1Facebook 1Twitter 7PinterestDiet plan for healthy weight loss; Maintain a healthy clean diet, and undertake regular exercise. That’s the simple truth. 

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This article and the lean body mass and body fat calculators provided are intended for informational purposes only, the results that you will get from this quality calculator are just estimations. Before making any decisions regarding diet, exercise or anything else relating to your health, you should consult with a medical expert.

Lean Body Mass Calculator
Article Name
Lean Body Mass Calculator
Use this lean body mass calculator to accurately measure and track both your lean body mass and your body fat percentage, to reach your perfect body goals.
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Sara Crave
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Ana Maria

As a certified strength coach and nutritionist, with a passion for living life and continual improvement, Ana Maria believes that every woman should bring out her inner goddess. A healthy active lifestyle, commitment to training and good nutrition are the keys. As the creator of Sara Crave, Ana Maria shares her passions for fitness, fun and fashion with you.

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