Health & Fitness

Lean Body Mass Calculator

How much of your weight is not fat?

By TheCalcTools Updated Formula checked and tested

Your numbers

Your results

Lean body mass (kg)
Lean body mass (kg)
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Estimated fat mass (kg)
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Estimated body fat
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Lean Body Mass Calculator by TheCalcTools

How the Lean Body Mass Calculator works

Enter your sex, weight and height.

The Boer formula estimates lean mass from weight and height.

Fat mass is the remainder.

The formula

Men: LBM = 0.407 W + 0.267 H − 19.2Women: LBM = 0.252 W + 0.473 H − 48.3

Worked example

Using the default values shown in the calculator:

SexMale
Weight (kg)80
Height (cm)180
  1. LBM = 0.407 × 80 + 0.267 × 180 − 19.2 = 61.4 kg.
  2. Fat mass = 80 − 61.4 = 18.6 kg, or 23.2% of body weight.

Result:

Lean body mass (kg)61.4
Estimated fat mass (kg)18.6
Estimated body fat23.2%

Frequently asked questions

How accurate is it?

It is a population-level estimate and can be off by several kilograms for an individual. DEXA scans and other methods are more accurate.

Why does lean mass matter?

It includes muscle, bone and organs and drives your metabolic rate, so it is useful for tracking training progress.

Sources and further reading

Body Fat CalculatorEstimate your body fat percentage from a tape measure, using the U.S BMR CalculatorEstimate how many calories your body burns at rest (BMR), and how many you use in a day… Ideal Weight CalculatorSee what four classic formulas suggest for your height BMI CalculatorCalculate your body mass index (BMI) from your height and weight, see which adult… Healthy Weight Range CalculatorWhat weights fall in the normal BMI range for your height? Body Surface Area (BSA) CalculatorBSA is used to scale drug doses and cardiac output

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This calculator gives general estimates for information and education. It is not medical advice and does not diagnose anything. Talk to a qualified health professional about your own situation. See our disclaimer.