Muscle Mass Calculator 💪

Estimate your Lean Body Mass (LBM) and Skeletal Muscle Mass (SMM).

1. Units & Personal Metrics

Select Weight Unit:

Gender

Age (Years)

Height (cm)

Weight (kg)

Body Composition Estimate

Skeletal Muscle Mass (SMM)

Lean Body Mass (LBM)

General Ranges for SMM %

Gender	Healthy Range (Age 20-40)
Male	40% - 50% of total body weight
Female	30% - 40% of total body weight

Calculation Method Explained (Simplified LBM)

Skeletal Muscle Mass (SMM) estimation is complex and typically requires medical imaging. This calculator uses a **simplified weight-based method** derived from estimating Lean Body Mass (LBM) first, which accounts for everything but fat (bones, organs, water, and muscle).

1. Estimating Lean Body Mass (LBM)

LBM is calculated using a factor based on average healthy body fat percentages for age and gender. This factor decreases as age increases to account for muscle loss (sarcopenia).

$$ \text{LBM}_{\text{kg}} = \text{Weight}_{\text{kg}} \times \text{LBM Factor} $$

2. Estimating Skeletal Muscle Mass (SMM)

On average, skeletal muscle makes up about 55% of your total Lean Body Mass (LBM). We use this approximation for the final SMM value:

$$ \text{SMM}_{\text{kg}} \approx \text{LBM}_{\text{kg}} \times 0.55 $$

The result is displayed in both mass units (kg/lb) and as a percentage of your total weight.