Lean Body Mass Calculator
Estimate lean body mass in kilograms using the Boer, James, and Hume formulas. Free and accurate.
Independently verified for accuracy
Calculator by Toolsloft ↗- Boer
- 61.42 kg
- James
- 62.72 kg
- Hume
- 57.79 kg
This calculator estimates lean body mass, the weight of everything in your body except fat, using three established formulas: Boer, James, and Hume. Comparing all three gives you a sensible range rather than a single point estimate.
How this is calculated
Lean body mass is derived from weight and height using published regression equations. The Boer formula is widely used in clinical settings, while the James and Hume equations offer alternative estimates. Each uses sex-specific coefficients. Results are in kilograms.
How to use
- Choose your sex, since each formula uses sex-specific coefficients.
- Enter your weight and height in metric, or switch the units to imperial to use pounds and inches.
- Read the three estimates from the Boer, James, and Hume formulas.
Examples
- Male, 80 kg, 180 cm:
Boer 61.42 kg - Female, 65 kg, 165 cm:
Boer 46.13 kg
FAQ
- What is lean body mass?
- Lean body mass is your total weight minus body fat. It includes muscle, bone, organs, and water. Tracking it helps you tell whether weight changes come from fat or from lean tissue.
- Why do the three formulas give different numbers?
- Boer, James, and Hume were each derived from different study populations and use different coefficients for weight and height. Small differences between them are normal, so treat the three results as a range rather than a single exact figure.