Which formula is most accurate?

Boer is widely cited as the most general-purpose. The average across formulas reduces individual model error.

How can I increase LBM?

Resistance training + adequate protein (≥1.6 g/kg) + recovery. Cardio alone won’t build LBM; it can preserve it during a deficit.

Why does my body fat % from LBM differ from a smart scale?

Different methods. LBM-based calculations and bioelectrical impedance use different inputs, so disagreements of 2–4% are normal.

Is muscle the same as lean body mass?

No — muscle is one component of LBM. LBM also includes bones, organs, water and connective tissue.

How often should I check LBM?

Every 4–8 weeks is plenty. Daily weight fluctuations are mostly water, not LBM.

Body measurements · Composition

Lean Body Mass Calculator

Calculate the weight of all your non-fat tissue.

Your details

Sex

Height

Weight

LBM formulas are estimates — DEXA and BodPod measurements remain the most accurate.

Average lean body mass

53.7kg

≈ 118.4 lb · implied body fat 23.3%

Boer (1984)54.7 kg

Hume (1966)51.1 kg

James (1976)55.3 kg

What is Lean Body Mass?

Lean Body Mass (LBM) is the weight of everything except fat — muscle, bone, water, organs, connective tissue. Tracking LBM rather than total weight is the smartest way to know whether a diet is preserving the tissue you care about.

The three classic formulas

We compute three estimates — Boer, Hume and James — and average them. Each was derived from a different population, so spread between them gives you a useful confidence interval.

When LBM is most useful

Dieting (preserve muscle), nutrition planning (protein at ≈1.6–2.2 g/kg LBM), drug dosing for some clinical contexts, and tracking long-term resistance-training progress.

Limitations & caveats

Formulas are estimates — error can be ±2 kg for an individual.
Don’t use during pregnancy.
May be less accurate for extreme builds (very low or very high body-fat percentages).
Use the same formula consistently when tracking changes over time.
For precise individual LBM, DEXA is the clinical reference.