Lean Body Mass Calculator
Calculate fat-free body mass
Formula
LBM = Weight × (1 - Body Fat %)
LBM = Total Weight - Fat Mass
LBM Components
| Muscle | ~40% of LBM |
| Bone | ~15% |
| Organs | ~10% |
| Water | ~35% |
Related
Complete Guide to Lean Body Mass Calculator
Lean Body Mass (LBM) is your total weight minus fat mass. It includes muscle, bones, organs, skin, and water - everything except stored fat. LBM is a key indicator of metabolic health and physical fitness.
Why LBM Matters
Higher lean mass means higher basal metabolic rate (you burn more calories at rest), better insulin sensitivity, stronger bones, and generally better health outcomes. Preserving LBM during weight loss is crucial.
LBM and Metabolism
Each pound of muscle burns approximately 6 calories per day at rest, compared to 2 calories for fat. While this difference seems small, over months and years it significantly impacts total calorie expenditure.
Protecting Lean Mass
- Eat adequate protein (1.6-2.2g/kg) especially when losing weight
- Do resistance training to signal your body to keep muscle
- Avoid extreme calorie deficits that promote muscle loss
- Get adequate sleep for recovery and hormonal balance
Frequently Asked Questions
LBM is your total weight minus fat. It includes muscle, bone, organs, water, and connective tissue. It's often confused with muscle mass, but muscle is only about 40% of LBM.
Higher LBM means higher metabolism, better insulin sensitivity, stronger bones, and improved physical function. Preserving LBM during weight loss prevents metabolic slowdown.
Resistance training is essential - it signals your body to build/maintain muscle. Eat adequate protein (1.6-2.2g/kg), get enough calories to support growth, and prioritize sleep for recovery.
Some LBM loss is normal during weight loss, but you can minimize it with adequate protein, strength training, and moderate calorie deficits. Crash diets cause excessive muscle loss.
LBM percentage is 100% minus body fat %. For healthy men, 75-85% LBM (15-25% body fat) is typical. For women, 65-80% LBM (20-35% body fat) is healthy.
Calculate LBM by measuring body fat percentage (Navy method, calipers, or DEXA scan) and subtracting fat mass from total weight. DEXA provides the most accurate LBM measurement.
Yes. BMR equations that use LBM (like Katch-McArdle) are more accurate than those using only total weight. More lean mass = higher calorie needs, even at rest.