Calculate your Lean Body Mass (LBM) accurately with our easy-to-use calculator. It employs scientifically validated formulas to estimate the weight of your muscles, bones, and organs, based on your age, gender, height, and weight. Get quick, personalized insights into your body composition.
Lean Body Mass Calculator
Lean Body Mass (LBM) Results:
| LBM Formula | Estimated Lean Body Mass (LBM) | Estimated Body Fat Mass (BFM) |
| Boer1 | ||
| James2 | ||
| Hume3 |
Lean Body Mass is defined as the total body weight minus body fat weight. It includes the weight of bones, muscles, blood, skin, and other non-fat tissues. LBM typically makes up about 60-90% of your total body weight, with men generally having a higher percentage than women.
LBM is crucial in various medical contexts. For instance, the dosing of certain water-soluble anesthetic drugs is often based on LBM. It’s also a key metric in some medical examinations. In fitness and everyday life, while body fat percentage often receives more attention, LBM remains an important indicator of overall health.
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
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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.
Lean Body Mass Formula
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).
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.
Lean Body Mass vs. Fat-Free Mass: Key Differences
Lean Body Mass (LBM) and Fat-Free Mass (FFM) are similar yet distinct terms in body composition analysis. LBM includes bones, muscles, water, ligaments, tendons, internal organs, and essential fats within organs. It excludes subcutaneous fat.
In contrast, FFM is the total body mass minus all fat mass, including essential and non-essential fats. Essentially, LBM is a component of FFM, with FFM being slightly lower due to the exclusion of essential fats. The difference is more pronounced in women (5-12%) than in men (2-3%), reflecting the higher essential fat content in the female body.
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:
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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.
References:
- Boer P. “Estimated lean body mass as an index for normalization of body fluid volumes in man.” Am J Physiol 1984; 247: F632-5
- James, W. “Research on obesity: a report of the DHSS/MRC group” HM Stationery Office 1976
- Hume, R “Prediction of lean body mass from height and weight.”. J Clin Pathol. 1966 Jul; 19(4):389-91.
- A. M. Peters, H. L. R. Snelling, D. M. Glass, N. J. Bird “Estimation of lean body mass in children”. British Journal of Anaesthesia1 06(5): 719-23 (2011).
Article Updates Timeline:
Our editorial team experts constantly update the articles with new information & research, ensuring you always have access to the latest and most reliable information.
January 5, 2024
Updated By
Matthew Magnante, ACE
Fact Checked By
Dr. Malik
January 13, 2022
Updated By
Editorial Team
April 25, 2020
Written By
Matthew Magnante, ACE
Reviewed By
Editorial Team
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