Use this free online lean body mass calculator to estimate the weight of your muscle, bone, and organs excluding body fat, using the Boer formula. Enter your gender, weight, and height to instantly see your estimated lean body mass and fat mass in kilograms.
How to Use the Lean Body Mass Calculator
Select your Gender from the dropdown.
Enter your Weight (kg) and Height (cm).
Click "Calculate Lean Body Mass" to see your lean body mass and fat mass results.
Frequently Asked Questions
This calculator uses the Boer formula. For men: LBM = (0.407 × weight) + (0.267 × height) - 19.2. For women: LBM = (0.252 × weight) + (0.473 × height) - 48.3, with weight in kilograms and height in centimeters.
Fat mass is simply your total body weight minus your estimated lean body mass, giving you a rough split between fat and non-fat body tissue.
If the formula produces a zero or negative value - which can happen with unusually low weight for a given height - the calculator shows an "Invalid input!" message since the result would not be realistic.
The Boer formula gives a population-level estimate based on weight and height only. It doesn't measure actual muscle or fat directly, so results are approximate and for general informational purposes only.