Lean Body Mass Calculator
Estimate how much of your body weight is lean mass versus fat using the Boer formula.
How to use the lean body mass calculator
- Choose units and your sex.
- Enter your weight and height.
- Click Calculate to see lean mass, fat mass and body-fat estimate.
Why lean mass matters
Lean mass drives your metabolic rate and strength potential, and many supplement and protein recommendations are scaled to it rather than total body weight.
Frequently asked questions
What is lean body mass?
Lean body mass is everything in your body that is not fat — muscle, bone, organs and water. It is a key reference for protein needs and dosing.
How accurate is the Boer formula?
It gives a solid estimate from height and weight alone, though a measured body-fat percentage (with our body-fat calculator) gives a more individualised figure.
Related tools
Body Fat Calculator
Estimate your body-fat percentage using the U.S. Navy circumference method — just a tape measure required.
FFMI Calculator
Measure your muscularity with the Fat-Free Mass Index, normalised for height.
Protein Intake Calculator
Find your daily protein target based on your body weight and training goal.