Lean mass guide
Lean Mass Calculator for Men
Estimate male lean body mass, fat mass, lean mass percentage, and protein targets with sex-specific formulas.
Last updated: · Reviewed by the Lean Mass Calculator editorial team
Who this page is for
Men comparing formula estimates with measured body fat percentage.
Start with the main lean mass calculator, then use the related tools below when you need body fat, FFMI, protein, or calorie context.
Interactive Calculator
Use this calculator to find your specific numbers before continuing with the guide.
Best formula choice for men
For men without a measured body fat percentage, the Boer equation is the best default on this site because it behaves well across common adult height and weight ranges.
If you know your body fat percentage from DEXA, calipers, or a consistent BIA device, use the direct body-fat method instead of any height-weight formula.
How to interpret the result
Lean mass includes muscle, bone, organs, connective tissue, and water. It is not the same as skeletal muscle mass.
For dieting, track whether lean mass is stable while body weight falls. If lean mass drops quickly, calories, protein, training, or measurement consistency may need attention.
Frequently asked questions
What is a good lean mass percentage for men?
Many healthy adult men fall around 75-90% lean mass, but age, training status, and body fat goals change the context.
Should men use FFMI too?
FFMI is useful when you want to compare fat-free mass relative to height, especially for strength or physique goals.
Sources & references
The estimates on this page use published lean body mass equations and clinical reference ranges. See the full reference charts on the lean body mass chart hub.
- Estimated lean body mass as an index for normalization of body fluid volumes — Boer P, American Journal of Physiology (PubMed) (1984)
- Percent Body Fat Norms and Reference Ranges — American Council on Exercise (ACE)
- Body Composition — Reference Information — National Institutes of Health (NCBI Bookshelf)