Lean Body Mass Calculator
Calculate your lean body mass (LBM) - the weight of everything in your body except fat, including muscle, bones, organs, and water.
Input
Enter your body fat percentage. If unknown, use our Body Fat Calculator first.
What is Lean Body Mass?
Lean Body Mass (LBM) is the total weight of everything in your body except fat. This includes muscle, bones, organs, water, and all other non-fat tissues. LBM is an important metric for tracking body composition changes, especially during weight loss or muscle-building programs.
Unlike total body weight, which can fluctuate due to water retention or fat changes, lean body mass is a more stable indicator of your actual body composition. Increasing LBM typically means you're building muscle, while maintaining LBM during weight loss indicates you're losing fat, not muscle.
How to Calculate Your Lean Body Mass
- Select your unit system (Metric or Imperial)
- Choose your gender
- Enter your current weight
- Enter your body fat percentage (use our Body Fat Calculator if you don't know it)
- Click "Calculate Lean Body Mass" to see your results
Understanding Your Results
- Lean Body Mass: Your total weight minus body fat. This includes muscle, bones, organs, and water.
- Body Fat Mass: The actual weight of fat in your body.
- Lean Body Mass Percentage: What percentage of your total weight is lean mass (the rest is fat).
Why Lean Body Mass Matters
- Metabolism: Muscle tissue burns more calories at rest than fat, so higher LBM means higher metabolism
- Strength: LBM correlates with strength and functional capacity
- Health: Maintaining or increasing LBM is associated with better health outcomes
- Weight Loss: Tracking LBM helps ensure you're losing fat, not muscle, during weight loss
- Muscle Building: Increasing LBM indicates successful muscle growth
Frequently Asked Questions
Q: How is this different from Body Fat Calculator?
A: The Body Fat Calculator estimates your body fat percentage and also shows LBM. This calculator focuses specifically on LBM and requires you to already know your body fat percentage. Use the Body Fat Calculator first if you need to measure your body fat.
Q: What's a good lean body mass percentage?
A: Good LBM percentages vary by gender and age. Generally, 75-85% for men and 65-75% for women are considered healthy. Athletes typically have higher percentages due to increased muscle mass.
Q: Can I increase my lean body mass?
A: Yes! Through resistance training, adequate protein intake, and proper recovery, you can increase your LBM. Building muscle takes time and consistency, but it's achievable with the right approach.
Q: Will my LBM decrease when I lose weight?
A: Some LBM loss is normal during weight loss, but you can minimize it by maintaining adequate protein intake, doing resistance training, and losing weight gradually (1-2 lbs per week).
Q: How often should I recalculate my LBM?
A: Recalculate monthly when tracking changes. LBM changes slowly, so daily or weekly measurements aren't necessary. Focus on long-term trends rather than short-term fluctuations.
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