FFMI Calculator
Fat Free Mass Index shows how much muscle you carry for your height, without counting body fat. Enter your measurements to get your score and see where it falls on the scale.
Your measurements
How to use
- Enter your height in centimeters, weight in kilograms and body fat percent.
- Choose the male or female interpretation scale.
- Press Calculate FFMI to see your score and category.
- Retest monthly to track lean muscle gains over time.
Note: The score is normalized to a height of 180 cm, which is the standard FFMI adjustment used in fitness research.
Tips
- Measure in the morning before eating for the most consistent readings.
- If your body fat number is only an estimate, the trend matters more than the exact score.
- An FFMI that rises while weight stays stable means you are gaining muscle and losing fat.
- Very high scores take years of training — be patient and keep lifting.
Frequently Asked Questions (FAQ)
What is FFMI?
FFMI stands for Fat Free Mass Index. It measures how much muscle you carry relative to your height, by removing fat from the calculation.
What is a good FFMI score?
For most men, 18 to 21 is athletic, 22 to 23 is very muscular, and above 23 is elite-level muscle. For most women, 16 to 18 is athletic and above 19 is very muscular.
Do I need an exact body fat percentage?
An exact number is not required. Use your best estimate from a scale, calipers, or a gym measurement. The calculator works with any reasonable input.
Why does it ask for a male or female scale?
The interpretation bands are different for men and women, so choose the matching scale to read your category correctly.