Lean Body Mass Calculator
Estimate lean mass and fat mass from height, weight and sex.
Enter values
kg
cm
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Step by step
The formula
Boer — male: 0.407·kg + 0.267·cm − 19.2; female: 0.252·kg + 0.473·cm − 48.3
Lean body mass is everything that is not fat — muscle, bone, organs and water. It matters because protein needs and many medication doses scale with lean mass rather than total weight, and because it is the part you generally want to keep during weight loss.
All calculations run locally in your browser and update instantly as you type.
Example calculations
Common questions this calculator answers — select one to load its values.
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Frequently asked questions
Why use lean mass instead of body weight?+
Protein requirements, many drug doses and metabolic rate all track lean tissue rather than total weight. Two people at the same weight with very different builds have quite different needs.
How accurate is the Boer formula?+
It is a reasonable population estimate from height and weight alone, but it cannot know your actual build. Very muscular or very lean individuals will be estimated poorly — DEXA is the reliable measurement.
All calculations run locally in your browser. Nothing you type is sent to a server.