Lean Body Mass Calculator

Calculate lean body mass (fat-free mass) using the Boer formula based on height and weight.

kg
cm
Lean Body Mass
Fat Mass
Body Fat %
Recent Calculations

What Is Lean Body Mass?

Lean body mass is everything in your body except fat: muscles, bones, organs, water, and other tissues.

Formula

Men: LBM = 0.407W + 0.267H − 19.2 Women: LBM = 0.252W + 0.473H − 48.3 (Boer formula)

Example

An 80 kg male, 178 cm tall has a lean body mass of approximately 60.1 kg.

Frequently Asked Questions

What's the difference between lean mass and muscle mass?

Lean mass includes everything except fat — muscles, organs, bones, and water. Muscle mass is just the muscle component.

Why does lean body mass matter?

It determines your base calorie needs and helps track whether weight changes come from fat loss or muscle loss.

Related Topics