Lean Body Mass Calculator
Estimate lean mass, fat mass, fat-free mass index and formula-based LBM using body fat percentage plus Boer, James and Hume equations.
Hit Calculate to see your body composition split
Calculate to classify the body fat input
Metrics appear after calculation
Your explanation appears here
Lean mass accuracy depends heavily on the body fat estimate. DEXA, 3D scans, calipers and smart scales can give different readings.
Your plan appears after calculation
Test how your lean and fat mass would change at a different body fat percentage while body weight stays the same.
Calculate your baseline first
It estimates lean body mass from your weight and body fat percentage, then compares that result with Boer, James and Hume formula estimates based on height, weight and sex.
No. Lean body mass is a mass value. FFMI adjusts fat-free mass for height, making it easier to compare body composition across different body sizes.
At the same body weight, a lower body fat percentage means a larger share of your weight is fat-free tissue. Real changes require consistent nutrition, training and measurement over time.
Results are estimates generated locally in your browser from body fat percentage and standard lean body mass equations. They are for informational purposes only, not medical, diagnostic or nutrition advice. Body composition devices vary in accuracy, and users with medical conditions, pregnancy, eating-disorder history or athletic weight-cutting needs should seek qualified professional guidance. VisionVix accepts no liability for decisions based on this output.
