Lean Mass Calculator: How to Calculate Ideal Lean Body Mass

The lean mass calculator is useful in knowing your lean body mass. But not a lot of people know about this so we will be explaining how to go about this here.

Lean Mass Calculator

There are two components that make up the body mass, lean body mass, and body fat. Oftentimes people wrongly use the words muscle mass and lean body mass interchangeably. They are two different things and knowing how to use a lean mass calculator will be of great help to you. Muscle mass, body fluids, and bones make up the lean body mass. Muscle mass describes your muscle size and it includes smooth, cardiac, and skeletal muscle. However, most times when people say muscle mass what they are talking about is the skeletal muscle. You need your skeletal muscle for balance, strength, and mobility. It also signals physical function and this is the reason why muscle building is recommended. 

When a person has decreased muscle mass, what it means is that your muscle is less than the average for your gender and age. On the other hand, increased muscle mass means it is above the average. Whether you will have high or low body fat depends on body composition. Measuring muscle mass can be difficult and it also depends on several factors like fitness level, ethnicity, and height. There are enough credible data on the average percentage of muscle mass. A reliable study conducted in the year 2000 had its researchers measuring the percentage of muscle mass in 468 males and females. The following was the result of the study. While there is a need for more research in the meantime we can refer to this.

Average Muscle Mass Percentage

For men

  • Age 18-35 (40-44%)
  • Age 36-55 (36-40%)
  • Age 56-75 (32-35%)
  • Age 76-85 (less than 31%)

For women

  • Age 18-35 (31-33%)
  • Age 36-55 (29-31%)
  • Age 56-75 (27-30%)
  • Age 76-85 (less than 26)

Lean Mass Calculator: How To Calculate Ideal Lean Body Mass

You don’t have to use an expensive calculator to calculate a lean body mass chart. There are scales, formulas, and calculators that help to make this possible. Although some of these are not proven to be accurate.

Here are some vital information about your lean body mass and muscle mass:

1. Use a percentage of body fat

You can use your percentage of body fat to know the percentage of your lean mass. How do you get the percentage of your fat? Use a fat scale and weigh yourself. 

This type of scale is specially designed with a bioelectrical impedance that causes an electrical current to travel through the user’s body. Fat is a poorer conductor of electricity than muscle hence, this current will be able to measure the amount of body fat available.

You will also input your weight, height, age, and gender. The scale needs this data together with its electrical current for the proper estimation of the percentage of body fat.

Subtract your percentage of body fat from 100 to give you your percentage of lean mass. For example, if your body fat is 30% that means your lean body mass is 70%. However, note that these scales are not always accurate but they are good estimates. Bmi and muscle mass calculator are also not very accurate.

2. The formula of U.S military 

There is a special formula used by the American military for estimating the percentage of body fat. Their method involves measuring body parts circumference. You can then use the measurement to find out your CV (circumference value).

Your height and CV should be placed on the chat with already calculated percentage estimates of body fat. With this number, you can estimate your percentage of lean body mass. 

For men, measure your neck and abdominal circumferences. Then get your CV by misusing the neck circumference from the abdominal circumference. 

For women, measure the neck, hip, and waist circumferences. Then get your CV by misusing your neck circumference from the total hip and waist circumference. 

Although the military makes use of this method, it is not 100% accurate. The measurement of circumference does not account for muscle size.

3. MRI

Magnetic resonance imaging is an accurate way of calculating the percentage of muscle mass. MRI captures your muscle images with strong magnets. In the machine, there are magnetic fields to rearrange the hydrogen atom of the body briefly. This will release energy for the machine to find out the muscle mass.

The gold standard in determining the percentage of muscle mass is MRI although it is quite expensive. It might not be the practical option for estimating the percentage of muscle mass.

How to Gain Muscle Mass

As you get older your muscle mass decreases but can be built back up through the right diet and exercise. Good nutrition and exercise will also assist in preserving your muscle mass. 


weight training or strength training is good for building muscle mass. They strengthen the muscle by working them against resistance. You can do exercises like:

  • Resistant band activities
  • Bodyweight exercises such as push-ups
  • Weight machines
  • Lift weights like soup cans and dumbbells
  • Do pilates
  • Do training at high intensity

It is usually recommended to have two to three sessions of strength training activities weekly. Cardio exercises are also important. Aerobic exercise such as dancing or jogging supports the growth of muscle and slows down muscle loss linked with muscle growth.


Keeping and gaining muscle mass depends also on the right nutrition. It includes eating sufficient nutritious calories for fueling the body. 

Protein helps in repairing and building muscle therefore they are particularly important. Your physical activity will determine how much protein is needed. Generally, ten to thirty-five percent of calorie intake daily should be from protein. 

Examples of food with high protein include; beef, fish, poultry, eggs, beans, and nuts. 

Carbohydrates are also needed to fuel muscle. Carbs should make up 50% of your calorie intake daily if you do strength training twice or more weekly. 

Also, enough intake of vitamins, minerals, or fat is needed to build your muscles. You should also avoid or limit processed food. Consumption of whole foods such as eggs and vegetables helps keep your muscles strong and healthy.

You will get the desired output on your lean mass calculator if you learn to properly balance your exercise and diet.

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