Fat-Free Mass Index — a better measure of body composition than BMI for active people. Accounts for muscle, not just weight.
📋 Source: FFMI formula and normalised FFMI: Kouri EM et al. Psychol Sci 1995. Reference ranges from body composition population studies. Your doctor or healthcare provider knows your history and circumstances — always follow their personalised advice over general information.
Don't know your body fat %? Try 15–20% for active men, 22–28% for active women, or leave blank to see FFMI range.
FFMI
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Normalised FFMI
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Adjusted to 1.80 m height
Lean body mass
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kg
BMI (for reference)
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May overestimate risk in muscular people
LowAverageAbove avgExcellentSuperior
Body fat percentage estimates introduce error into FFMI calculations. For precise body composition, DEXA scanning is the gold standard. FFMI is a research and fitness tool — it is not used clinically to diagnose conditions. Discuss any concerns about weight, body composition, or muscle mass with your GP or an accredited practising dietitian.
Sources
Kouri EM, Pope HG, Katz DL, Oliva P. Fat-free mass index in users and nonusers of anabolic-androgenic steroids. Clinical Journal of Sport Medicine. 1995;5(4):223–228. doi:10.1097/00042752-199510000-00003
Schutz Y, Kyle UUG, Pichard C. Fat-free mass index and fat mass index percentiles in Caucasians aged 18-98 y. International Journal of Obesity. 2002;26:953–960. doi:10.1038/sj.ijo.0802037