FFMI Calculator

Calculate your Fat-Free Mass Index to assess muscle development and natural potential.

%

Use a body fat calculator or measurement method to determine this

Height

Weight

Currently using Imperial units

Calculate Your FFMI

Enter your measurements to calculate your Fat-Free Mass Index and assess your muscle development potential.

About Fat-Free Mass Index (FFMI)

Understanding FFMI

  • Fat-Free Mass Index: A metric that measures muscle mass relative to height, similar to BMI but for lean mass only
  • Normalized FFMI: Adjusts your FFMI to a standard height of 180cm (5'11") for fair comparison
  • Natural Limit: Research suggests FFMI values above 25 are uncommon without performance-enhancing substances
  • Genetic Variation: Individual genetics can affect natural muscle-building potential
  • Training History: Years of consistent training significantly impact achievable FFMI

FFMI Categories

  • Below Average (< 18): Lower than typical muscle mass for height
  • Average (18-20): Normal range for general population
  • Above Average (20-22): Good muscle development from training
  • Excellent (22-23): Competitive natural athlete level
  • Superior (23-25): Near maximum natural potential
  • Suspicious (25-26): Exceeds typical natural limits
  • Unlikely Natural (> 26): Beyond established natural limits