FFMI Calculator
Measure your muscularity with the Fat-Free Mass Index.
Your Results Will Appear Here
Fill in the form to see your FFMI score.
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What is FFMI?
FFMI stands for Fat-Free Mass Index. It is used to calculate the amount of muscle mass you have relative to your height. This index is commonly used by bodybuilders and fitness enthusiasts to compare themselves to others. FFMI is also a useful alternative to the standard Body Mass Index (BMI), as BMI does not differentiate between fat and muscle mass.
FFMI Formula
Total Body Fat = Weight * (body fat [%] / 100)
Lean Weight = Weight * (1 - (body fat [%] / 100))
The core formulas are:
FFMI = (Lean Weight in kg) / (Height in m)2
Adjusted FFMI = FFMI + (6.3 * (1.8 - Height in m))
Note: Our calculator performs all conversions and calculations automatically for you, regardless of the unit system you choose.
FFMI Interpretation
The calculated FFMI score can be interpreted using the tables below. Note that the interpretation differs for men and women.
FFMI Score for Men
| FFMI | Body Fat | Description |
|---|---|---|
| 17-18 | 10-18% | Skinny man |
| 18-20 | 20-27% | Average man |
| 19-21 | 25-40% | Fat man |
| 20-21 | 10-18% | Athlete / Intermediate gym user |
| 22-23 | 6-12% | Advanced gym user |
| 24-25 | 8-20% | Bodybuilder / Powerlifter / Weightlifter |
FFMI Score for Women
| FFMI | Body Fat | Description |
|---|---|---|
| 14-15 | 20-25% | Skinny women |
| 14-17 | 22-35% | Average women |
| 15-18 | 30-45% | Fat women |
| 16-17 | 18-25% | Athlete / Intermediate gym user |
| 18-20 | 15-22% | Advanced gym user |
| 19-21 | 15-30% | Bodybuilder / Powerlifter / Weightlifter |
How to Use This Calculator
- Choose your preferred measurement system (Metric or US).
- Select your gender.
- Enter your current weight and height.
- Enter your body fat percentage. You can use the slider for a quick estimate or type the exact value.
- Click the "Calculate FFMI" button to get your results.
Frequently Asked Questions (FAQ)
What is FFMI and why is it useful?
FFMI stands for Fat-Free Mass Index. It measures your muscle mass relative to your height, making it a more accurate indicator of muscularity than BMI, especially for athletes and bodybuilders, because it separates muscle mass from fat mass.
What is a good FFMI score?
A 'good' FFMI score depends on your goals. For men, a score of 20-21 is typical for an athlete, while 22-23 is considered advanced. For women, 16-17 is athletic and 18-20 is advanced. Scores above 25 for men and 22 for women are very high and may indicate exceptional genetics or use of anabolic steroids.
How is FFMI different from BMI?
Body Mass Index (BMI) calculates a score based on your total weight and height, without distinguishing between fat and muscle. FFMI is superior for athletic individuals because it only considers fat-free mass (muscle, bone, organs), providing a true measure of muscularity.
How can I increase my FFMI?
To increase your FFMI, you need to build more muscle mass (increase your fat-free mass). This is typically achieved through a combination of consistent resistance training (weightlifting) and a proper diet with sufficient protein and calories to support muscle growth.
Is a high FFMI always good?
Generally, a higher FFMI indicates more muscle, which is often associated with better health and athletic performance. However, extremely high FFMI scores (above 25 for men, 22 for women) are difficult to achieve naturally and can sometimes be an indicator of steroid use. It's important to focus on sustainable, healthy progress.