FFMI Calculator

FFMI stands for Fat Free Mass Index, which measures the amount of muscle mass relative to height. It's an alternative to Body Mass Index (BMI) that specifically focuses on lean muscle mass rather than total body weight.

FFMI is calculated using the formula: FFMI = (Lean Weight in kg) / (Height in meters)². The calculation involves determining your total body fat mass, calculating your lean mass (total weight minus body fat), and dividing lean mass by height squared.

FFMI is the raw calculation of muscle mass relative to height. Normalized FFMI adjusts for height differences, making it easier to compare individuals of different heights. The normalization formula accounts for the fact that taller people naturally have more potential for muscle mass.

FFMI categories provide context for your muscle mass level: Below Average indicates low muscle mass; Average represents typical muscle mass; Above Average shows good development from training; Excellent indicates significant muscle mass; Superior represents exceptional development.

FFMI calculation accuracy depends on the accuracy of your body fat percentage measurement. The most accurate methods include DEXA scans, hydrostatic weighing, or BodPod testing. Skinfold calipers and bioelectrical impedance scales provide reasonable estimates for most people.