Fat-Free Mass Index which takes height and weight into account and used to describe muscle mass of a person. FFMI is correlated with BMI although having some differences as well. FFMI is not used commonly as BMI but is more precise and used for particular people like Bodybuilders and athletes.
The fat-free mass index uses three factors to measure muscle mass in body which are:
Here is the table of scores that can be used by anyone to know where they stand regarding muscle mass and how much they can gain naturally and with the use of steroids.
The following tables classify the FFMI indexes:
For men:
| Description | Body fat percent | FFMI range |
| Skinny guy | 10-18 | below 18 |
| Average weighted guy | 20-27 | 18-20 |
| Obese guy | 25-40 | 20-22 |
| Athlete/ gym user | 10-18 | 22-23 |
| Gym freak | 6-12 | 23-26 |
| Heavyweight Bodybuilder/ professional athlete | 8-20 | 26-28 |
| Steroid user with regular gym | 8-20 | More than 28 |
The above FFMI chart shows FFMI ranges for men, here is a table that shows FFMI ranges in women.
| Description | Body fat percent | FFMI range |
| Skinny girl/woman | 20-25 | 14-15 |
| Average weighted woman | 22-35 | 14-17 |
| Obese woman | 30-45 | 15-18 |
| Athlete/ gym user | 18-25 | 16-17 |
| Gym freak | 15-22 | 18-20 |
| Heavy weight Body Builder/ professional athlete | 15-30 | 19-22 |
There are several formulas used widely to calculate body FFMI and other related measures. Here are the formulas according to each measurement:
Total Body Fat = Weight in Kg × (body fat % / 100)
Lean Weight = Weight in Kg × (1 - (body fat % / 100)
FFMI = (Lean Weight in Kg / 2.2)/ ((Feet × 12.0 + Inches) × 0.0254)2
Attuned FFMI = FFMI + (6.3 × (1.8 - (Feet × 12.0 + Inches) × 0.0254))
These formulas allow you to calculate muscle mass in the human body but to save time you can use our calculator for free. Furthermore, you can freely switch between units according to your understanding and knowledge on our calculators like for height you can use cm, meter, inches and feet.
To use our calculator all you need is to follow these quick steps:
BMI is a prediction rule with classified norms that tells if a person is underweight, average or overweight. However, this parameter has limitations as it uses the only weight of a person and neglecting lean body mass and fat in the body.
BMI shows same results for two persons with different height and body structure just like if a person with a lot of muscles and other person with swollen belly; BMI will show same results for both as weight in both people is same and this is one reason BMI is not used for professional athletes, heavy weight lifters and others.
On the other hand, FFMI takes height and body fat into account and give out precise results showing actual muscles mass of a person.
There is a difference between gaining weight in an unhealthy way which is not a good thing and gaining muscles while doing exercise and using a proper diet. FFMI is what distinguishes between muscle gain and fat gain.
If fat in the body increases FMI decreases and vice versa. FFMI is used in the different medical field as well, as it estimates correctly health condition of a person. For persons doing exercise and achieving health goals, BMI is useless for them. FFMI is what can help them out for the regular checkup of their muscle mass. Use our calculator and FFMI according to the need while sitting in-home or anywhere else.
BMI is not totally useless it has its own advantages vary situation to situation. You can calculate your Body mass index as well by using our BMI calculator.