Calzivo

Health & Fitness Calculators

Lean Body Mass

Estimate your lean body mass and body composition.

Select gender

Selected: Male

Select units

Selected: US units

Enter your details to see your body composition results.

What is Lean Body Mass?

This estimate uses the Boer formula. Lean Body Mass (LBM) is the amount of weight you carry on your body that isn't fat. It includes your bones, muscles, organs, skin, and water. Knowing your LBM helps in calculating your nutritional needs more accurately than just total body weight.

Formula and example

The Boer formula estimates lean body mass from weight, height, and gender. The result is not a direct body scan.

Male formula: 0.407 x weight kg + 0.267 x height cm - 19.2. Female formula: 0.252 x weight kg + 0.473 x height cm - 48.3.

Example: a male at 82 kg and 178 cm has an estimated lean body mass of about 61.7 kg by the Boer formula.

Safety and limitations

Body-composition formulas are estimates, not medical advice or diagnosis.

Results can be less accurate for athletes, pregnancy, older adults, people under 18, and anyone with unusual body composition or a medical condition.

Practical uses

  • Estimate how much total weight may be non-fat mass.
  • Compare body-composition context alongside BMI or body fat estimates.
  • Use as rough nutrition-planning context, not a diagnosis.

Common mistakes

  • Treating lean body mass as muscle mass only.
  • Using formula estimates as if they were body scans.
  • Ignoring hydration, training status, pregnancy, age, or medical context.
  • Using the result to diagnose, treat, or manage a health condition.

Transparency note

Accuracy and limitations

Calzivo tools are built for practical estimates, conversions, and checks. Some tools use standard formulas or simplified assumptions, and results can be affected by input accuracy, rounding, units, local rules, or changing official requirements.

Health and fitness results are estimates, not medical advice. Formulas simplify real bodies and cycles, so important health decisions should be checked with a qualified clinician.

How to Use This Tool

Use these steps to enter the right inputs and interpret the result correctly.

1

Choose gender and unit system.

2

Enter weight and height in the selected units.

3

Press Calculate Lean Body Mass to estimate lean mass, fat mass, and body fat percentage.

4

Use the result as a formula estimate, not a body-composition diagnosis.

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Calorie Calculator

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Ideal Weight Calculator

Estimate ideal weight range from height and the Devine formula.

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Body Fat Calculator

Estimate body fat percentage from body measurements or a rough BMI-based method with general category guidance.

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Macro Calculator

Calculate your ideal macronutrient breakdown.

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Related Guides

Background reading and explanations related to Lean Body Mass.

BMI Explained (What It Means and When It Misleads You)

What your BMI score really means.

Read Guide

BMI Limits: What BMI Can and Cannot Tell You

Understand BMI as a screening estimate and where body composition context matters.

Read Guide

Ideal Weight Is an Estimate, Not a Diagnosis

Read ideal-weight formula results as rough context, not medical conclusions.

Read Guide

Frequently Asked Questions

Common questions about Lean Body Mass and how to read the result.

What is lean body mass?

Lean body mass is the estimated body weight that is not fat, including muscle, bone, organs, water, and other non-fat tissue.

Which formula does this use?

This calculator uses the Boer formula, which estimates lean body mass from height, weight, and gender.

Is lean body mass the same as muscle mass?

No. Lean body mass includes muscle, but it also includes bone, organs, water, and other non-fat tissue.

How accurate is this estimate?

It is a rough formula estimate. It can be less accurate for athletes, pregnancy, older adults, or unusual body composition.

Can this diagnose body fat percentage?

No. It should not be used to diagnose, treat, or manage a medical condition. More direct body-composition methods may be needed.

Who should use professional guidance?

People under 18, pregnant people, older adults, athletes, and anyone with a medical condition should use professional guidance.