Lean Body Mass Calculator

Written by Great Medico

Updated September 24, 2026 •2 min read

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One body-size number rarely tells the whole story, but it can answer a precise question. Lean Body Mass Calculator is built for that narrower job.

What this calculator does

Lean body mass estimates how much of body weight is not fat. This calculator uses height, weight, and sex to provide a quick equation-based estimate without requiring a body-fat percentage measurement. Anthropometric equations are convenient because they use simple measurements, but they describe body size or proportion rather than directly measuring tissue composition or health.

How to use it

Enter or select Sex, Height, and Weight. Use the units offered by the calculator and keep measurements consistent when you plan to compare results over time.

How the calculation works

The calculation uses the sex-specific Boer equations, which combine body weight and height with different coefficients for males and females. The output is lean body mass in the selected weight unit.

Example

For the sample values prefilled in this calculator, the primary result is 56.02 kg (Lean body mass (Boer)). This example is there to show how the inputs flow through the implemented equation; replace the sample values with your own measurements before using the result.

How to interpret the result

Use the result as an estimate of non-fat mass, which includes muscle, organs, bone, body water, and other lean tissues. It is not the same thing as skeletal muscle mass.

Limitations and notes

Boer equations were derived from population data and can be less accurate at body-size extremes or when fluid status is abnormal. Because the method does not directly measure body composition, DXA or other validated techniques may give a different value. For repeat measurements, consistency usually matters more than false precision: use the same unit system, the same tape or scale when possible, and the same anatomical landmarks. A small change near a category boundary should be viewed in context rather than treated as a sudden biological change.