Lean Body Mass Calculator
Estimate lean body mass with Boer, James, and Hume equations using your height, weight, and sex.
| Formula | LBM | Lean % |
|---|---|---|
| Boer | 136 lbs | 75.2% |
| James | 139 lbs | 76.9% |
| Hume | 127.3 lbs | 70.4% |
| Average | 134.1 lbs | 74.2% |
Lean Body Mass Percentage RangesMEN
These bands interpret lean body mass as a percentage of total body weight. Use the result as a directional fitness metric, not a diagnosis.
| RANGE | CATEGORY |
|---|---|
0-70% | Very Low Lower lean-mass share for body weight. Recheck measurements and monitor trends. |
70-75% | Low Below typical male lean-mass percentage ranges. |
75-80% | Healthy Within common healthy lean-mass ranges for men. |
80-85% | Good Solid lean-mass share often seen with regular training. |
85-90% | Athletic Athletic range with higher lean-mass proportion. |
90-95% | Exceptional Unusually high lean-mass percentage. Verify inputs for realism. |
95+% | Rare Very rare naturally. Double-check height and weight entries. |
What This Lean Body Mass Calculator Shows
Lean body mass (LBM) is everything in your body except fat: muscle, organs, bone, and body water. This calculator estimates your LBM from height and weight using three commonly cited formulas and shows both absolute lean mass and lean-mass percentage.
Use these numbers to track trend direction over time. Absolute values can vary by formula, hydration status, and how closely your body matches the assumptions in each equation.
Formulas Used
This tool calculates three standard LBM equations and provides an average:
Boer
Men: LBM = 0.407 x weight(kg) + 0.267 x height(cm) - 19.2
Women: LBM = 0.252 x weight(kg) + 0.473 x height(cm) - 48.3
James
Men: LBM = 1.10 x weight(kg) - 128 x (weight/height)^2
Women: LBM = 1.07 x weight(kg) - 148 x (weight/height)^2
Hume
Men: LBM = 0.32810 x weight(kg) + 0.33929 x height(cm) - 29.5336
Women: LBM = 0.29569 x weight(kg) + 0.41813 x height(cm) - 43.2933
The formula table in the results panel highlights your selected method so you can compare how each equation shifts the estimate.
How To Interpret Your Result
Higher lean body mass can reflect more muscle and generally a lower fat share, but context matters. Height, frame size, and training history all affect what is realistic. For frame-only context, run the Body Frame Size Calculator.
For weekly tracking, use the same conditions and compare trend movement rather than chasing a perfect one-time value.
If you want a skeletal-muscle-specific estimate from circumferences and skinfolds, use the Muscle Mass Calculator.
If you want body-fat context alongside this result, use the Body Fat Calculator or the RFM Calculator. For waist-centered roundness, add the BRI Calculator, and for hip-height adiposity use the BAI Calculator.
Lean Body Mass vs FFMI
Lean body mass is an absolute amount (kg or lbs). FFMI adjusts lean mass for height so muscularity comparisons are fairer across different body sizes.
After estimating LBM, use the FFMI Calculator if you want a height-normalized muscularity score.
References
- Boer P. Estimated lean body mass as an index for normalization of body fluid volumes in humans.PubMed record
- Janmahasatian S, et al. Quantification of lean bodyweight.PubMed record
- Pai MP. Drug dosing based on weight and body size in obese adults.Free full text (PMC)