Lean Mass Calculator for Bodybuilders
Track lean mass and height-adjusted FFMI for physique goals.
Built by Menang7, owner of LeanMassCalculator.com
Lean Mass vs Muscle Mass →Lean Body Mass vs Muscle Mass
Lean mass is not the same as muscle. Learn what each number includes before you set a physique goal.
What is FFMI?
Fat-free mass index (FFMI) is your lean mass in kilograms divided by your height in metres squared. Bodybuilders use it because the scale alone cannot tell fat from muscle, and body weight does not say how developed a physique is for a given height.
This calculator also gives a normalized FFMI, which adds 6.1 × (1.8 − height in metres). Lean mass tends to rise faster than height squared, so taller people get higher plain FFMI values. The adjustment scales everyone to a 1.8 m reference height, so you can compare builds of different heights.
The formulas
| Measure | Calculation |
|---|---|
| Lean mass | Weight × (1 − body fat %), or the Boer formula if no body fat is entered |
| FFMI | Lean mass (kg) ÷ height (m)² |
| Normalized FFMI | FFMI + 6.1 × (1.8 − height in m) |
FFMI ranges
| Category | Women | Men |
|---|---|---|
| Low | Below 14 | Below 18 |
| Average | 14–17 | 18–20 |
| Above average | 17–19 | 20–22 |
| Excellent | 19–22 | 22–25 |
| Very high | Above 22 | Above 25 |
A rough guide, not a verdict. Body fat readings carry error, so one number cannot settle how a physique was built.
Examples at 12% body fat
| Height | Weight | Body fat | Lean mass | FFMI | Normalized |
|---|---|---|---|---|---|
| 170 cm | 80 kg | 12% | 70.4 kg | 24.4 | 25.0 |
| 180 cm | 85 kg | 12% | 74.8 kg | 23.1 | 23.1 |
| 190 cm | 100 kg | 12% | 88.0 kg | 24.4 | 23.8 |
Notice that the 170 cm and 190 cm lifters share the same plain FFMI of 24.4, yet their normalized values differ (25.0 and 23.8). That is the height adjustment at work.
Using lean mass in a bulk or cut
Frequently asked questions
Fat-free mass index (FFMI) is your lean mass in kg divided by height in metres squared. It shows how much non-fat tissue you carry for your height, which makes it popular for tracking physique progress.
For men, 20–22 is above average and 22–25 is usually reached after years of consistent training. Values above 25 are rare in drug-free lifters, though a single number is not proof of anything.
Lean mass tends to rise faster than height squared, so taller people end up with higher plain FFMI values. The normalized FFMI adds 6.1 × (1.8 − height in metres) to scale everyone to a 1.8 m reference height, so builds of different heights can be compared fairly.
The result is only as good as your body fat reading. Skinfold calipers, smart scales and visual estimates can be off by several percent, so use the same method every time and follow the trend. A DXA scan is more precise.
No. Lean mass includes muscle, bone, organs, skin and water, so it is larger than muscle alone. Read the guide on lean body mass vs muscle mass for the full breakdown.
Related
About Menang7, the developer
This calculator is part of LeanMassCalculator.com, developed, owned and maintained by Menang7. For questions about how it works or your results, Menang7 is the person to look for.
For personal medical or nutrition decisions, please also speak with a doctor or registered dietitian.