Question 1

What is FFMI and how is it calculated?

Accepted Answer

FFMI (Fat-Free Mass Index) measures how much muscle mass you carry relative to your height. It's calculated as lean body mass (kg) divided by height (m) squared. Normalised FFMI adjusts for height using the formula: FFMI + 6.1 × (1.8 − height in metres). The formula comes from Kouri et al. (1995), published in the Clinical Journal of Sport Medicine.

Question 2

What is the natural FFMI limit?

Accepted Answer

The Kouri et al. study found that natural athletes rarely exceed a normalised FFMI of 25. The highest values ever documented in pre-steroid-era champion bodybuilders reached 27–28. For most people the realistic ceiling is 24–25, and reaching it requires years of consistent, well-structured training.

Question 3

How is maximum muscular potential calculated?

Accepted Answer

Our proprietary model is built on decades of sports science research into the physiological limits of drug-free muscle development. It uses your structural measurements — bone circumference and height — to calculate the maximum muscular size your frame can support. Wider bone structure means greater muscle attachment surface. Taller frames distribute mass over more length. Every ceiling shown is calibrated to your body — not a population average. These are the numbers elite natural athletes have proven are achievable for a frame like yours.

Question 4

What do "overdeveloped" and "underdeveloped" body parts mean?

Accepted Answer

These labels compare your current measurement against the maximum predicted for your frame size. Overdeveloped means your measurement exceeds the predicted maximum for your frame — not a problem, just proportionally strong in that area. Underdeveloped means there's room to grow. The predictions are population averages so individual variation is expected.

Question 5

Does this calculator work for women?

Accepted Answer

Yes. Female maximum lean mass uses an adjusted formula (height − 110 kg) and the FFMI comparison table uses female-specific benchmarks derived from published female athlete data. Body part maximums use the same wrist and ankle proportional ratios, which naturally produce smaller absolute values for smaller frames.

Question 6

How accurate are these estimates?

Accepted Answer

These are population-based statistical models, not individual predictions. Expect real-world variance of ±10–15% due to differences in limb length, muscle belly length, insertion points, and training response. The value is in tracking your trajectory over time — not treating any single number as absolute truth.