Enter your height, weight, and body fat percentage into the calculator below to determine your fat-free mass index, known as FFMI. FFMI is a measure of muscle mass in relation to your height and weight. Compare your results with the table below.
FFMI Formula
The following formula is used by this calculator to determine your FFMI:
FFMI = (w*(1-bf%/100))/ (h [m])²
- Where FFMI is the fat-free max index
- w is your weight (lbs)
- bf% is your body fat percentage (%)
- h is your height (meters)
FFMI Definition
FFMI stands for fat-free mass index and is a measure of muscle mass in relation to your height and weight.
What does my FFMI mean?
The higher your FFMI the more muscle mass you have compared to your body area. Anything above 58 is unlikely to occur naturally in humans. Therefore, people with an FFMI greater than 58 likely used steroids.
FFMI depends on height, weight, and body fat percentage. As a result, the only way to change your FFMI is to either lose body fat% or gain muscle. In reality, gaining muscle will lower your body fat percentage, so it’s a direct correlation.
What is a healthy FFMI?
There is no set value for a healthy FFMI, but in general body fat percentages between 10-205 are considered healthy.
