Lean Body Mass Calculator
Calculate your lean body mass and body fat composition.
Body Composition
Typical ranges: Men 10-20%, Women 18-28% (athletes lower, sedentary higher)
Body Composition
Lean Body Mass
56.0
kilograms
(80.0% of total weight)
Body Fat Mass
14.0
kilograms
(20% of total weight)
Total Weight Breakdown:
About This Calculator
The Lean Body Mass Calculator helps you determine your lean body mass (LBM) and body fat mass based on your total weight and body fat percentage. Lean body mass includes muscle, bone, organs, and water - essentially everything except fat.
Understanding your lean body mass is important for tracking fitness progress, determining protein needs, and assessing body composition changes. As you lose weight, maintaining or increasing lean body mass while reducing fat is the goal for healthy body recomposition.
Formula & Calculation Method
Lean Body Mass Calculation:
Body Fat Mass = Total Weight × Body Fat Percentage
Lean Body Mass = Total Weight - Body Fat Mass
Lean Body Mass % = (Lean Body Mass ÷ Total Weight) × 100
Alternative (Boer Formula for Men):
LBM = 0.407 × Weight(kg) + 0.267 × Height(cm) - 19.2
Alternative (Boer Formula for Women):
LBM = 0.252 × Weight(kg) + 0.473 × Height(cm) - 48.3
This calculator uses body fat percentage to determine lean body mass. Body fat percentage can be measured using various methods including DEXA scan, BIA (bioelectrical impedance), calipers, or body composition scales. More accurate methods provide more precise LBM calculations.
How to Use This Calculator
- Enter Weight: Input your total body weight in kilograms.
- Enter Body Fat Percentage: Input your body fat percentage (from DEXA, BIA, calipers, or estimates).
- View Results: See your lean body mass, body fat mass, and percentages.
Frequently Asked Questions
What is a good lean body mass?
Lean body mass varies by individual, gender, height, and genetics. Men typically have higher LBM than women. Generally, higher LBM relative to total weight indicates better body composition. Focus on maintaining or increasing LBM while reducing body fat percentage.
How do I measure body fat percentage?
Methods include DEXA scan (most accurate), BIA scales/devices, caliper measurements, BodPod, and visual estimates. Accuracy varies - DEXA is gold standard, while BIA and calipers provide good estimates. Consistency in measurement method is important for tracking changes.
Why is lean body mass important?
LBM is important because it includes muscle mass, which affects metabolism, strength, and functional capacity. Higher LBM increases resting metabolic rate. When losing weight, preserving LBM helps maintain metabolism and prevents muscle loss.
Can I increase lean body mass?
Yes! Resistance training, adequate protein intake (1.6-2.2g per kg), sufficient calories (or slight surplus for muscle gain), and proper recovery all support increasing LBM. New lifters and those returning to training can see faster gains.
NumCalculators Editorial Team
Multi-disciplinary Expert Team
The NumCalculators Editorial Team consists of subject matter experts across various fields who review and verify the accuracy of our calculators. Each calculator undergoes rigorous testing and validation before publication.