Who Built This Calculator
FFMI Calculator Pro was built by an engineer with a postgraduate degree in engineering management. He is a fitness enthusiast who brings technology into his own training routine, using data to plan workouts, measure body composition and track progress over time.
That mix of engineering and lifting shaped the tool. Many FFMI calculators online use outdated constants, rough unit conversions or no sources at all. This one was built to get the math right, show its working and explain what the numbers mean.
How the Calculator Was Made
The calculator was built after a thorough research process. Every formula on the site comes from published research:
- FFMI and normalized FFMI follow Kouri et al. (1995), using the 6.1 height constant from the original paper.
- Population ranges and percentiles draw on Schutz et al. (2002).
- The tape-measure body fat estimate uses the US Navy equations by Hodgdon and Beckett for men and women.
- Units convert with exact factors (2.20462 lb per kg, 2.54 cm per inch), so switching between pounds and kilograms never changes your result.
The full list of research sources is in the Sources section of the calculator page.
Our Approach to Accuracy
The information on this site is thorough and reliable to the best of our knowledge. It is checked against the original studies and updated when better evidence becomes available. If you spot an error, please contact us and we will review it.
Medical Disclaimer
FFMI Calculator Pro is for education and general information only. It is not medical advice and does not diagnose or treat any condition. Talk to your physician or a qualified health professional before changing your diet, training or health routine. In case of an emergency, contact your physician or call your local emergency number right away. Read the full disclaimer.