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Lean Body Mass Calculator — Global, Accurate, SEO Optimized
LBM

Lean Body Mass Calculator

Accurate Lean Body Mass (LBM) for all countries. Mobile-first, SEO-optimized, with a 3D doughnut chart.

Calculate your Lean Body Mass

No sliders. Works globally with metric/imperial units. Choose a formula; we’ll also show other formulas for comparison.

Your results

Primary LBM
— kg
Estimated fat mass
— kg
LBM share of body weight
—%
Other formulas (reference)
Boer — kg
James — kg
Hume — kg
Body Fat % — kg
Practical guidance
Protein Aim ~1.6–2.2 g/kg LBM/day
Strength 2–4 sessions/week supports LBM
Recheck Update after weight or routine changes

3D doughnut chart

Percent labels show the share of Lean Body Mass vs Fat Mass.

Lean body mass calculator guide: Understand fat-free mass and real progress

Lean Body Mass is everything in your body minus fat: muscle, bone, organs, and water. Tracking LBM helps you set realistic goals, calibrate protein intake, and protect strength during fat loss. This calculator supports multiple evidence-based formulas and global units for clarity and accessibility.

Which LBM formula should I choose?

  • Boer: A robust default for most adults; uses weight and height with gender-specific constants.
  • James: Includes a non-linear weight term; sometimes underestimates at higher body weights.
  • Hume: Another validated choice with height and weight; similar to Boer in many cases.
  • Body Fat % method: If you know your body fat reasonably well, LBM = Weight × (1 − BF%).

How to use your results

  • Protein planning: Many aim for 1.6–2.2 g per kg of LBM per day to support muscle.
  • Training focus: Combine resistance training with progressive overload to maintain or build LBM.
  • Weight changes: Recalculate if your body weight or routine changes; trends matter more than single readings.

Tips for students and professionals

  • Batch meals: Center meals around protein, vegetables, whole grains, and fruit.
  • Short lifts: 30–45 minute strength sessions fit busy schedules and still move the needle.
  • Sleep & steps: Recovery and gentle daily movement improve body composition outcomes.

Limitations & notes

  • Estimates: Formulas have error margins. Use consistent methods and track trends.
  • Body fat input: If uncertain about BF%, prefer formula-based LBM (e.g., Boer) until you get better estimates.
  • Medical context: Special populations may need clinical assessment beyond equations.
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