FFMI Calculator
Fat-free mass index: how much muscle you carry for your height.
That is above average for men (women typically score about 3 to 4 points lower).
How do you calculate FFMI?
Work out your fat-free mass, then divide it by your height squared: FFMI = weight × (1 − body fat %) ÷ height (m)². The normalised version adds 6.1 × (1.8 − height in m) so tall and short lifters compare fairly. For example, 80 kg at 15% body fat and 1.78 m gives 68 kg of fat-free mass and an FFMI of about 21.5.
FFMI ranges (men)
| Normalised FFMI | What it means |
|---|---|
| Below 18 | Below average |
| 18 to 20 | Average |
| 20 to 22 | Above average |
| 22 to 23 | Excellent |
| 23 to 25 | Superior |
| 25 and above | Near or beyond the natural upper range |
Source: Kouri et al., Clinical Journal of Sport Medicine, 1995. Women typically score about 3 to 4 points lower.
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What is a good FFMI?
For men, a normalised FFMI of 20 to 22 is above average and 22 to 23 is excellent for someone who trains. Women typically score about 3 to 4 points lower for the same level of training.
What is the natural FFMI limit?
A 1995 study of drug-free lifters found few above a normalised FFMI of about 25. It is a guide, not a hard rule: genetics, measurement error and body-fat estimates all move the number.
How accurate is my FFMI?
Only as accurate as your body-fat figure. A 3% error in body fat shifts FFMI by roughly 0.7 points, so use the same measurement method each time and watch the trend.
Related: what FFMI means · body fat calculator · lean body mass calculator