Skip to main content

FFMI Calculator – Fat-Free Mass Index

Calculate your Fat-Free Mass Index to evaluate muscle mass

This calculator is for informational purposes only and not a substitute for professional medical advice.
Calculate FFMI

How to Use

  1. Enter your weight in kilograms or pounds
  2. Enter your height in centimeters or feet
  3. Enter your body fat percentage
  4. Click calculate to see your FFMI result

What is FFMI?

Fat-Free Mass Index (FFMI) is a measure of lean body mass relative to height. It's calculated by dividing your lean body mass (weight minus fat mass) by your height squared. FFMI is particularly useful for bodybuilders, athletes, and fitness enthusiasts to track muscle development.

Normalized FFMI adjusts the score to account for height variations, making it easier to compare results across different individuals regardless of their height.

FFMI Categories

Normalized FFMICategoryDescription
Below 17Below AverageLower muscle mass
17 - 19AverageTypical for untrained individuals
19 - 21Above AverageGood muscle development
21 - 23ExcellentWell-trained athletes
23 - 25SuperiorElite bodybuilders
Above 25Suspiciously HighMay indicate steroid use

How to Improve Your FFMI

  • Follow a structured resistance training program
  • Consume adequate protein (1.6-2.2g per kg of body weight)
  • Maintain a slight caloric surplus for muscle growth
  • Get 7-9 hours of quality sleep per night
  • Manage stress levels effectively
  • Stay consistent with training and nutrition
  • Track progress over time
  • Consider working with a qualified trainer or nutritionist

Frequently Asked Questions

What is a good FFMI score?
For men, an FFMI of 19-21 is considered above average, while 21-23 is excellent. For women, 15-17 is above average. Scores above 25 are rare without performance-enhancing substances.
How is FFMI different from BMI?
BMI only considers total body weight and height, while FFMI specifically measures lean body mass (muscle, bone, organs) relative to height, providing a more accurate assessment of muscular development.
How accurate does my body fat percentage need to be?
FFMI accuracy depends on accurate body fat measurements. Use reliable methods like DEXA scans, hydrostatic weighing, or calibrated calipers for best results.
Can I use FFMI to detect steroid use?
While FFMI above 25 is often associated with steroid use, it's not definitive proof. Some genetic outliers can achieve higher scores naturally, but it's extremely rare.

Related Calculators

health
Ankle-Brachial Index (ABI) Calculator

Screen for peripheral artery disease by comparing ankle and arm blood pressure

health
Blood Alcohol Content (BAC) Calculator

Calculate your Blood Alcohol Content (BAC) level and impairment category

health
Absolute Neutrophil Count (ANC) Calculator

Calculate Absolute Neutrophil Count to assess infection risk