FFMI Calculator
Calculate your Fat-Free Mass Index to track muscle growth and physique.
Your FFMI Score
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Normalized FFMI (for height)
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This is an estimate for informational purposes and is not a substitute for professional medical or fitness advice.
About the FFMI Calculator
The Fat-Free Mass Index (FFMI) is a scientifically validated measurement that indicates how muscular you are relative to your height, after accounting for your body fat. Unlike BMI, which can be misleading for athletic individuals, FFMI provides a true measure of your lean physique, making it an excellent tool for tracking progress in the gym.
Formula Explained
The calculator uses two key formulas:
- Fat-Free Mass (FFM): First, we calculate your lean body mass.
FFM = Weight[kg] × (1 - (Body Fat % / 100)) - FFMI: Then, we calculate your FFMI using your FFM and height.
FFMI = FFM / (Height[m]²) - Normalized FFMI: Finally, we adjust the score for your height.
Normalized FFMI = FFMI + 6.1 × (1.8 - Height[m])
How to Improve Your FFMI Score
Improving your FFMI means increasing muscle mass while managing body fat. Here are some effective strategies:
Progressive Overload
Consistently challenge your muscles by gradually increasing the weight, reps, or sets in your strength training routine.
Adequate Protein Intake
Consume enough protein (around 0.8-1 gram per pound of body weight) to support muscle repair and growth.
Prioritize Sleep
Aim for 7-9 hours of quality sleep per night, as this is when your body releases growth hormone and repairs muscle tissue.
Stay Hydrated
Proper hydration is crucial for muscle function, nutrient transport, and overall performance in the gym.
Frequently Asked Questions
What is a good FFMI score? →
For men, an FFMI of 18-20 is considered average, 20-22 is above average, 22-25 is considered muscular, and above 25 is typically very muscular and may be difficult to achieve naturally. For women, 14-16 is average, 16-18 is above average, and above 19 is considered muscular.
What is the difference between FFMI and BMI? →
Body Mass Index (BMI) only considers height and weight, and cannot distinguish between fat and muscle. Fat-Free Mass Index (FFMI) is a more advanced metric because it accounts for body fat percentage, providing a much better indicator of one's muscularity.
How do I measure my body fat percentage? →
There are several methods to measure body fat percentage. The most accessible methods include using skinfold calipers or a bioelectrical impedance scale. For more accurate results, you could consider a DEXA scan or hydrostatic weighing, though these are less common and more expensive.
What is normalized FFMI? →
Normalized FFMI adjusts your score based on your height. Taller individuals naturally have a slight advantage in the standard FFMI calculation. The normalized formula adds a small adjustment to level the playing field, providing a more comparable score for people of different heights.
Can FFMI indicate steroid use? →
Some studies suggest that a normalized FFMI score above 25 is a strong indicator of potential anabolic steroid use, as this level of muscularity is very difficult for most natural athletes to achieve. However, it is not a definitive test and should be considered an indicator, not proof.