body composition

FFMI Calculator

Calculate fat-free mass index, lean mass, and height-normalized FFMI from bodyweight, height, and body fat percentage inputs.

Body composition

Trend tracking

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SexHeight (cm)Weight (kg)Body fat %

Body fat

15%

Manual input

Lean mass

69.7kg

153.7 lb

FFMI

21.5

Raw FFMI 21.5

Calculate fat-free mass index, lean mass, and height-normalized FFMI from bodyweight, height, and body fat percentage inputs.

Body composition

Trend tracking

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How the body composition estimate works

Circumference and FFMI formulas are useful for trend tracking, not diagnosis. Use the same measurement method each time and watch the direction across weeks.

Related calculators

Training guides

Body Fat Calculator

Estimate body fat percentage with Navy circumference or Jackson-Pollock 3-site skinfold inputs, then calculate lean mass and FFMI.

Questions lifters ask

How should I use the FFMI Calculator? +

Use the output as a starting estimate, track actual bodyweight and performance for two weeks, then adjust based on trend data.

Is this medical advice? +

No. These calculators are for general training planning. Work with a qualified professional if you have medical conditions or disordered eating history.