Estimate the weight of everything in your body except fat — muscle, bone, organs, water, and tissue.
Your Measurements
kg
cm
cm
cm
cm
cm
⚠ Please enter weight and height to calculate.
Your Results
Lean Body Mass
—
kg
Fat Mass
—
kg
Body Fat %
—
%
LBM as % of body weight—
—
—
Formula Comparison
Formula
LBM
Fat Mass
Body Fat %
How to Interpret Your Results
Category
Body Fat % — Men
Body Fat % — Women
Description
Essential Fat
2–5%
10–13%
Minimum fat required for organ & hormonal function
Athletic
6–13%
14–20%
Typical of competitive athletes; high muscle definition
Fitness
14–17%
21–24%
Above average fitness; healthy and lean
Average
18–24%
25–31%
Acceptable range; some excess fat present
Obese
25%+
32%+
Elevated health risks; consult a healthcare provider
Note: Body fat % ranges are general guidelines (American Council on Exercise). Individual variation exists — athletes may have higher LBM at the same body fat %, and age affects typical ranges. Women naturally carry more essential fat than men due to reproductive physiology.
About the Formulas
📐
Boer (1984)
Derived from a large dataset; widely considered the most accurate for general populations. Uses weight and height only.
Developed primarily for clinical use and pediatric/ICU settings. Uses body weight only, making it simpler but less precise for healthy adults.
LBM = 3.8 × 0.0215 × W⁰·⁶⁵⁰² × H⁰·⁷²³⁶
Why Lean Body Mass Matters
💊
Drug & Supplement Dosing
Many medications — particularly anesthetics, certain antibiotics, and chemotherapy drugs — are dosed on LBM to avoid toxicity, since fat tissue doesn't distribute many drugs the same way muscle does.
🔥
Metabolic Rate
LBM is the primary driver of your Basal Metabolic Rate (BMR). More lean mass means a higher resting metabolism, which helps with long-term weight management and energy levels.
🏋️
Tracking Training Progress
Scale weight alone is misleading. LBM allows you to see whether you're building muscle or losing it — especially important during a cut, bulk, or body recomposition phase.
🦴
Bone & Functional Health
Preserving LBM as you age reduces risk of sarcopenia (muscle loss), osteoporosis, and frailty. Higher lean mass is associated with greater longevity and functional independence.
🥗
Protein & Calorie Targets
Protein requirements are often calculated based on LBM (e.g. 1.6–2.2g per kg of LBM for those training), giving more accurate targets than total body weight, especially for higher body fat individuals.
📈
Clinical Assessment
In clinical and hospital settings, LBM helps clinicians assess nutritional status, hydration, and fluid requirements — especially in critically ill or malnourished patients.
Tips to Increase Lean Body Mass
🏃
Resistance Training
Progressive overload with weights (or bodyweight) 3–4× per week is the most effective stimulus for muscle protein synthesis and LBM gain.
🥩
Adequate Protein Intake
Aim for 1.6–2.2g of protein per kg of LBM daily. Prioritise leucine-rich sources: chicken, fish, eggs, dairy, legumes, and quality protein supplements.
😴
Quality Sleep
Growth hormone — essential for muscle repair — is predominantly released during deep sleep. 7–9 hours of quality sleep per night is non-negotiable for LBM preservation and growth.
⚖️
Appropriate Calorie Balance
A slight caloric surplus (200–300 kcal) supports muscle gain while limiting fat accumulation. Aggressive deficits increase muscle catabolism — lose fat slowly to preserve LBM.
This calculator provides estimates based on validated mathematical formulas.
It is not a substitute for professional medical advice, diagnosis, or treatment.
For clinical body composition assessment, consult a qualified healthcare provider or use DEXA scanning.