FFMI Calculator

Calculate Fat-Free Mass Index (FFMI) to assess muscle mass and body composition with athletic comparisons and natural genetic limit analysis

Example Profiles

Gender

Age (years)

Weight

Height

Body Fat Percentage (%)

Use DEXA scan, BodPod, or caliper measurements for accuracy

Activity Level

What is FFMI?

Fat-Free Mass Index normalizes muscle mass for height, similar to BMI but focusing on lean tissue only.

Why Use FFMI?

• More accurate than BMI for athletes

• Assesses muscle development potential

• Helps detect natural vs enhanced physiques

• Tracks muscle gain/loss over time

Natural Limits:

• Men: Typically 25-26 maximum naturally

• Women: Typically 22-23 maximum naturally

• Genetic outliers may exceed these ranges

Body Fat Measurement:

• DEXA scan: Most accurate (±2-3%)

• BodPod: Very accurate (±3-4%)

• Calipers: Good if done properly (±4-5%)

• Bioelectrical: Less accurate (±5-8%)

Important Notes:

• Accuracy depends on precise body fat %

• Use consistently over time for trends

• Consider alongside other health metrics

• Adjusted FFMI accounts for height differences