Empower your health journey by accurately estimating and optimizing your lean mass. Whether you’re an athlete aiming for peak performance or someone striving for better health, understanding lean mass is a crucial step toward your goals.
Lean Body Mass (LBM) Calculator
Enter your weight (kg), height (cm), and select your gender to calculate your lean body mass using the James formula.
* Note: For males, LBM = 1.10×weight – 128×(weight²/height²); for females, LBM = 1.07×weight – 148×(weight²/height²).
Step 1: Enter Your Data
Enter your weight in kilograms.
Enter your height in centimeters.
Select your gender.
How It Works
The James formula for estimating lean body mass is: $$ \text{LBM} = \begin{cases} 1.10 \times \text{Weight} – 128 \times \left(\frac{\text{Weight}^2}{\text{Height}^2}\right) & \text{(Male)} \\ 1.07 \times \text{Weight} – 148 \times \left(\frac{\text{Weight}^2}{\text{Height}^2}\right) & \text{(Female)} \end{cases} $$
Ensure that weight is in kilograms and height is in centimeters.
Understanding Lean body mass (LBM)
Lean body mass (LBM) is the weight of your body minus the weight of your fat mass. It includes the weight of your bones, muscles, organs, skin, body water, connective tissue, and stored glycogen.
How to calculate LBM
- To calculate LBM, you can subtract your fat mass from your total body weight. For example, if you weigh 80 kg and have 30% body fat, your fat mass is 24 kg, and your LBM is 56 kg.
- You can also use mathematical formulas to estimate LBM. For example, the Boer formula for men is LBM = (0.407 × W) + (0.267 × H) − 19.2, where W is body weight in kilograms and H is body height in centimeters.
Why calculate LBM?
Calculating LBM can help you track whether weight gain or loss is due to fat or LBM. This can help you make more informed nutrition and training choices.
Other terms for LBM
LBM is also sometimes known as "lean mass" or "lean soft tissue"
What does lean body mass (lbm) include?
LBM can further be subdivided into muscle mass, body water, and bone mass. These two approaches are commonly referred to as a two-compartment model (LBM and BFM) or a four-compartment model (BFM, muscle mass, body water and bone mass) for assessing body composition.
A healthy lean body mass (LBM) is typically between 70% and 90% of your total body weight. However, the exact percentage depends on your age, gender, and fitness level.
Lean body mass by gender
- Men: Lean body mass is usually higher, ranging from 80% to 90%.
- Women: Lean body mass is usually lower, ranging from 70% to 85%.
Factors that affect lean body mass
- Age: Lean body mass naturally declines with age.
- Fitness level: Athletes often have even leaner body compositions.
Calculating lean body mass
You can calculate your LBM by subtracting your body fat weight from your total body weight. You can also use a body composition monitor to measure your body fat percentage.
Benefits of lean body mass
A higher percentage of LBM is associated with better metabolic health and overall well-being. LBM is also used by anesthesiologists to dose certain medications.