Estimate lean body mass using body weight, body fat percentage, and common formulas like Boer, James, and Hume. This free lean body mass calculator supports men and women, US and metric units, and shows multiple lean mass estimates in one place.
Body fat method:
Lean body mass = body weight × (1 − body fat percentage).
Boer formula:
Uses height and body weight to estimate lean body mass.
James formula:
Another well-known formula based on weight and height ratio.
Hume formula:
Uses height and body weight in a slightly different clinical estimate.
Lean body mass can help give a better picture of body composition than total body weight alone. It is often used for fitness tracking, body composition analysis, and nutrition planning.
Changes in lean body mass can be useful when tracking training progress over time.
Your result shows lean body mass using several methods, along with estimated fat mass and lean mass percentage based on your body fat input.
This helps compare direct body-composition math with common formula-based estimates.
Lean body mass is your total body weight minus fat mass. It includes muscle, bone, water, and organs.
No. Muscle mass is part of lean body mass, but lean body mass also includes other non-fat tissues.
If you know body fat percentage, the direct body fat method is usually the most straightforward estimate.
Each formula was developed differently, so they can produce slightly different lean mass estimates.