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  1. Home
  2. Health & Fitness
  3. Lean Body Mass Calculator

Lean Body Mass Calculator

Calculate your Lean Body Mass (LBM) using multiple validated formulas. Determine your fat-free mass for fitness and health planning.

Formula:LBM = Weight × (1 - Body Fat %)

Body Composition

Lean Body Mass

135.6 lbs

75.3% of body weight

Fat Mass44.4 lbs
Body Fat %24.7%
Lean Mass %75.3%
Formula UsedBoer

Body Composition

Lean Body Mass

135.6 lbs

75.3% of body weight

Fat Mass44.4 lbs
Body Fat %24.7%
Lean Mass %75.3%
Formula UsedBoer

Basic Information

Measurements

Body Composition

Lean Body Mass

135.6 lbs

75.3% of body weight

Fat Mass

44.4 lbs

24.7% of body weight

Formula Comparison

FormulaLBMBody Fat %
Boer135.6 lbs24.7%
James138.5 lbs23.1%
Hume126.9 lbs29.5%
Peters132.0 lbs26.7%

Average LBM: 133.2 lbs

What Lean Body Mass Includes

Muscles

40-50%

Bones

15%

Organs

10-15%

Water & Blood

20-25%

Explore Body Composition Scenarios

Explore how changes affect your results

Your Lean Body Mass vs Population

Compared to the general population

Your LBM Percentage

75.3 %

Percentile

27th

There's room for improvement

Distribution

You

Low

70.0

Below Avg

75.0

Average

80.0

Fit

85.0

Athletic

90.0

Your Ranking

Top 73%

73% are lower

Body Composition Tips

Based on your results

0/5 completed
⚕️ MedicalImportant

Your Composition

At 75.3% lean mass (135.6 lbs), your focus on fat loss while preserving muscle.

🏃 ExerciseImportant

Build Muscle

To build lean mass, aim for slight calorie surplus, 0.8-1g protein per lb bodyweight, and progressive strength training 3-4x/week.

🥗 NutritionRecommended

Protein for LBM

To maintain/build your 136 lbs of lean mass, aim for 136g protein daily.

Quick Answer

Lean Body Mass = Total Weight - Fat Mass. LBM includes muscle, bone, organs, and water. Boer formula (men): 0.407×weight(kg) + 0.267×height(cm) - 19.2. Average LBM: 60-90% of body weight.

Key Facts

  • LBM = everything except fat
  • Includes muscle, bone, organs, water
  • Multiple estimation formulas exist
  • Higher LBM = higher metabolism
  • Preserving LBM important during weight loss
  • Athletes have higher LBM percentage

Frequently Asked Questions

Lean Body Mass is your total body weight minus fat mass. It includes muscles, bones, organs, skin, blood, and water. LBM is important for determining metabolic rate, medication dosing, and fitness goals. Higher LBM generally indicates better metabolic health.

Total weight minus fat. Includes muscle, bone, organs, water. Important for metabolism and fitness.

LBM is estimated using formulas based on height and weight. Common formulas include Boer (most accurate for average adults), James (good for both genders), and Hume (validated in clinical settings). Each uses different coefficients but relies on the same inputs.

Formulas using height and weight. Boer most accurate for average adults.

Healthy LBM varies by gender. Men typically have 75-85% LBM (15-25% body fat). Women typically have 65-75% LBM (25-35% body fat) due to essential fat differences. Athletes may have higher LBM percentages.

Men: 75-85% LBM. Women: 65-75% LBM. Athletes typically higher.

Increase LBM through resistance training, adequate protein intake (0.7-1g per pound of bodyweight), progressive overload, and sufficient recovery. Focus on compound exercises like squats, deadlifts, and presses. Maintain a slight caloric surplus for muscle gain.

Resistance training, 0.7-1g protein/lb, progressive overload, adequate recovery.

Each formula was developed using different populations and methodologies. Boer is considered most accurate for average adults. James works well across genders. Hume was validated in clinical settings. Use the average or the formula most suited to your demographics.

Different study populations and methods. Use average or formula matching your demographics.

Body Composition

Lean Body Mass

135.6 lbs

75.3% of body weight

Fat Mass44.4 lbs
Body Fat %24.7%
Lean Mass %75.3%
Formula UsedBoer

Medical Disclaimer

This calculator is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult with a qualified healthcare provider before making any health-related decisions.