Lean Body Mass Calculator

Calculate your lean body mass and fat-free weight using multiple formulas.

Result

Fill in the fields above, then press Calculate.

A lean body mass calculator estimates the weight of everything in your body except fat, including muscle, bone, organs, and water.

Enter your weight, height, and gender. The calculator estimates your lean body mass using three formulas (Boer, James, Hume) and shows the average. It also calculates your estimated fat mass and body fat percentage.

Examples

170 lb, 5'9" male

Weight: 77 kg, Height: 175 cm. Boer: 0.407(77) + 0.267(175) - 19.2 = 59.5 kg. Average LBM across all formulas: approximately 62 kg (137 lbs).

Frequently Asked Questions

What is lean body mass?
Lean body mass is your total body weight minus all fat weight. It includes muscle, bone, organs, water, and other non-fat tissue. It is not the same as muscle mass alone.
Why does LBM matter?
LBM is used to calculate medication dosages, estimate metabolic rate, and set nutritional targets. Higher LBM relative to total weight generally indicates better fitness and metabolic health.
Related Calculators
Body Fat Percentage Calculator
BMI Calculator
Ideal Weight Calculator
One-Rep Max Calculator

Quick Tips

  • •Track your lean body mass over time to monitor changes in body composition rather than just total weight.
  • •Combine LBM estimates with body fat percentage for a more complete picture of your fitness.
  • •Use LBM to set more accurate protein intake targets — aim for 1.6-2.2g per kg of lean mass for muscle building.