Lean Body Mass (LBM) Calculator

The LBM or Lean Body Mass Calculator is a convenient tool for determining your body composition. Our calculator is based on three different formulas that calculate lean body mass which is composed of muscle, bone, tissue, organs, skin, blood, and water.

Lean Body Mass Calculator

Imperial Metric

Please fill out the form correctly

Male Female

age

weight

height

Lean Body Mass (LBM) Results:

LBM Formula	Estimated Lean Body Mass (LBM)	Estimated Body Fat Mass (BFM)
Boer¹
James²
Hume³
Age 14 or younger:
Peters (for Children)⁴

Fat is not included in lean body mass but the percentage of fat mass is provided in the results when your LBM is calculated.

The four formulas used in the LBM calculation include…

Boer
James
Hume
Peters (children’s formula)

The formulas for each are as follows… Note: The calculation for each formula varies due to the fact that each is typically used for different medical purposes (e.g. CT scans, administering medications, etc).

Lean Body Mass Formula

Boer formula

For men: LBM = (0.407 × W) + (0.267 × H) − 19.2

For women: LBM = (0.252 × W) + (0.473 × H) − 48.3

W is weight in kilograms and H is height in centimeters

James formula

For men: eLBM = 1.1W – 128(W/H)^2

For women: eLBM = 1.07W – 148(W/H)^2

W is weight in kilograms and H is height in centimeters

Hume formula

For men: LBM = (0.32810 × W) + (0.33929 × H) − 29.5336

For women: LBM = (0.29569 × W) + (0.41813 × H) − 43.2933

W is weight in kilograms and H is height in centimeters

Peters formula

The Peters formula is used for children aged 13-14 years old or younger.

eECV (extracellular volume) = 0.0215.W^0.6469.H^0.7236

eLBM = 3.8.eECV

W is weight in kilograms and H is height in centimeters

Which formula is the most accurate?

That’s a good question that we don’t necessarily have enough information to confidently answer. The Boer and James formulas are within 1% of each other though. Although, the Hume formula isn’t far off but it can be 3-4% higher than the other two formulas on average.

How To Use The LBM Calculator

Our LBM calculator is extremely simple to use.

Step 1: Choose your unit of measurement (imperial or metric)

Step 2: Select your gender

Step 3: Type in your age, weight, and height

Step 4: Hit calculate

You’ll then get your estimated lean body mass and estimated body fat mass.

Frequently Asked Questions

What is the lean body mass (LBM) calculator used for?

“Our” lean body mass (LBM) calculator is used to determine the ratio of lean body mass (muscle, bone, blood, skim, water) to fat mass.

But, the mathematical formulas used for the calculator are typically used for medical reasons (e.g. CT scan, medication dosing).

Does the lean body mass calculator tell me how much body fat I have?

The LBM calculator does provide an estimated percentage of fat mass in addition to the estimated lean body mass percentage.

What's a good lean body mass percentage?

It varies and typically ranges between 60-90% of bodyweight.

For women, the average lean body mass percentage is between 69 and 75 percent while the average for men is typically around 76 and 82 percent.

Women naturally have a higher body fat percentage for healthy function which is why this also varies.

People who are active and play sports usually have a higher lean body mass percentage compared to sedentary or naturally leaner individuals.

What's considered an unhealthy lean body mass percentage?

Because the average lean body mass percentage for women is between 69 and 75 percent while the average for men is typically around 76 and 82 percent, anything outside of this range could be considered to be unhealthy.

If you have too little or too much body fat, your chances of experiencing health issues increases.

How to improve your LBM to fat mass ratio

Exercising regularly and eating several, healthy meals throughout the day will ensure you maintain muscle mass while keeping body fat to healthy levels.

Strength training in combination with a reasonable daily caloric intake is ideal for maintaining healthy body composition.

Also try our other calculators:

Wrapping Up

There’s nothing complex about this calculator or the information which it provides. It likely won’t be 100% accurate but the results are determined from an estimate. It’s a good tool to use however as it can provide somewhat of a starting point for your goals.