Are you in good shape? See how you measure up.
FFMI (fat free mass index) is a formula to quantify muscle development based on your height, weight, and body fat.
With the FFMI calculator, you’ll find your fitness category. See how you compare to your friends and get tips to improve your score.
Lean Mass & Height
Weight distribution is different for taller and shorter people. For that reason, FFMI is normalized to average height. Or about 5’11” for men and 5’4″ for women. You’ll see both numbers in the results section of the FFMI calculator.
Of course, the taller you are the more lean mass you can fit on your frame. So taller people weigh more at the same FFMI as shorter people.
The graphs below show the FFMI ranges for different heights.
You can use these charts to see how much lean mass you would need to reach the different FFMI categories.
Find your height on the vertical axis and travel across the graph until you intersect the desired category. Then travel down to find your target lean mass on the horizontal axis.
For example, a 5’9″ male would need at least 154 lbs of lean mass to be “extremely muscular”. And a 5’3″ female would need about 101 lbs of lean mass to be “very well built”.
What Is A Good FFMI?
When trying to define a good FFMI, it’s useful to look at a large population. One study sampled over 5,000 men and women and compiled their FFMI data2.
I’ve plotted that data here in what’s called a normal distribution or ‘bell curve’. So you can see where the majority of people fall on the FFMI scale.
|Top 5%||Above 22.5|
|Top 10%||Above 21.5|
|Top 25%||Above 20.5|
|Top 50%||Above 19.5|
Based on this data, guys should shoot for an FFMI of at least 19.5 to be above average. But keep in mind this is compared to a random population, not necessarily lifters.
To stand out among gym bros, you might need to target an FFMI over 21.5
|Top 5%||Above 18.5|
|Top 10%||Above 17.5|
|Top 25%||Above 16.5|
|Top 50%||Above 15.5|
According to these numbers, girls should aim for an FFMI of at least 15.5 to be above average. Again, that’s compared to a random population.
An FFMI above 17.5 would be more likely to get you noticed.
How to Improve FFMI
It’s important to consider body fat along with FFMI when determining how to improve your physique. Because you could have a high FFMI and not be in good shape.
For example, top-level sumo wrestlers are extremely muscular and have very high body fat levels. That’s useful for pushing opponents around, but it’s not the look most of us want.
Therefore, it’s a good idea to focus on reducing body fat if you’re in the overweight or obese categories.
Male Body Fat Categories
Female Body Fat Categories
The “Gym Persona” matrix is intended to make it easy to see which way to go. If you’re in the first two columns you should work on moving to the right.
Once you have your body fat under control, start gaining muscle in order to move down.
At the end of the day, a “good” FFMI is only relative to your starting point. If you’re just beginning, don’t be intimidated by comparing yourself to others. Aim for incremental improvements and strive for your personal best.
FFMI is a useful tool for men and women to assess their current level of fitness. Compared to BMI it’s more accurate and representative of the active population.
In addition, FFMI can predict a naturally attainable goal for your frame. Which helps you determine how to adjust your diet and training to get there.
If you had fun with this FFMI calculator please share it with your friends. And check out my other free tools.
1) Kouri, Elena M., et al. “Fat-free mass index in users and nonusers of anabolic-androgenic steroids.” Clinical journal of sport medicine: official journal of the Canadian Academy of Sport Medicine 5.4 (1995): 223-228.
2) Schutz, Y., U. U. G. Kyle, and C. Pichard. “Fat-free mass index and fat mass index percentiles in Caucasians aged 18–98 y.” International journal of obesity 26.7 (2002): 953-960.