FFMI Calculator
Calculate your Fat-Free Mass Index to assess your level of muscularity.
Understanding FFMI
The Fat-Free Mass Index (FFMI) is a measurement that assesses your muscularity relative to your height. Unlike BMI, which only considers height and weight, FFMI accounts for body composition, making it a more useful tool for athletes, bodybuilders, and fitness enthusiasts.
Key Factors Explained
- Fat-Free Mass: This is your total body weight minus your body fat. It includes muscle, bones, organs, and water.
- Height: Your height is used to normalize your fat-free mass, allowing for a fair comparison between people of different heights.
- Adjusted FFMI: This calculator also provides an "Adjusted FFMI," which is normalized to a height of 1.8 meters (5'11"). This is the standard measurement used in most clinical studies.
The FFMI Formula
The calculation for FFMI involves a few steps:
- Calculate Lean Body Mass (LBM): `LBM (kg) = Weight (kg) * (1 - (Body Fat % / 100))`
- Calculate FFMI: `FFMI = LBM (kg) / (Height (m))^2`
- Calculate Adjusted FFMI: `Adjusted FFMI = FFMI + 6.1 * (1.8 - Height (m))`
Frequently Asked Questions (FAQ)
What is a good FFMI score?
A "good" score depends on your gender and goals. For men, an adjusted FFMI of 22-25 is considered quite muscular. For women, a score of 18-21 is considered muscular. Scores above 25 for men may indicate a very high level of muscularity, sometimes associated with steroid use, though it is achievable naturally by some.
How is FFMI different from BMI?
Body Mass Index (BMI) doesn't distinguish between fat and muscle. A very muscular person can have a high BMI and be classified as "overweight" or "obese." FFMI solves this by using body fat percentage to isolate your muscle mass, providing a much more accurate picture of your muscular development.
Is this FFMI calculator accurate?
The mathematical calculation is accurate. However, the accuracy of your result depends entirely on the accuracy of your body fat percentage input. Methods like calipers, hydrostatic weighing, or DEXA scans provide more accurate body fat readings than bioelectrical impedance scales.
For a more in-depth guide, read our detailed article on this topic.