Lean Body Mass Calculator

Use this lean body mass calculator to estimate your total weight minus body fat using validated clinical formulas (Boer, James, Hume) for accurate medication dosing and fitness tracking.

How to use this calculator

1. Select your gender and unit system.
2. Enter your total weight and height.
3. Compare LBM estimates across Boer, James, and Hume clinical formulas.

Formula & method

Boer, James & Hume LBM Formulas

Male Boer LBM = 0.407 × Weight(kg) + 0.267 × Height(cm) − 19.2

Female Boer LBM = 0.252 × Weight(kg) + 0.473 × Height(cm) − 48.3.

Example

Male 70 kg at 175 cm: Boer LBM ≈ 55.9 kg (80% lean mass, 20% fat mass).

Key insights

• Lean body mass consists of muscle, bone, organ tissue, fluids, and essential fat.
• The Boer equation is often considered the standard for drug dosing calculations in clinical settings.
• LBM is a better predictor of basal metabolic rate (BMR) than total body weight.
• Increasing lean body mass through strength training elevates daily calorie burning at rest.

How to interpret your result

Lean Mass (LBM)

Total weight of all body components excluding non-essential adipose fat.

Fat Mass

The weight of body fat calculated by subtracting average LBM from total weight.

Frequently asked questions

What is the difference between LBM and muscle mass?

LBM includes muscle mass plus bones, organs, water, and blood, whereas muscle mass counts skeletal muscle only.

Why calculate lean body mass?

It helps determine accurate protein targets, calorie requirements, and precise clinical drug dosages.

Related calculators

• Body Fat Calculator — Estimate your body fat percentage, fat mass, and lean mass using the US Navy method.
• Army Body Fat Calculator — Compute body fat percentage using US Army AR 600-9 circumference tape test.
• BMI Calculator — Compute your Body Mass Index and see where you stand, in metric or imperial units.

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