FFMI Calculator (Fat-Free Mass Index)
Calculate your FFMI to assess muscle mass relative to height. Adjust for body fat percentage and track your fitness progress over time.
Step 1: Basic Measurements
FFMI Formula
FFMI = [Weight in kg × (1 – Body Fat % / 100)] ÷ (Height in m)²
Normalized FFMI = FFMI + 6.1 × (1.8 – Height in m)
Step 2: Options & Units
FFMI Categories
Below Average: < 18 (Men), < 15 (Women)
Average: 18-20 (Men), 15-17 (Women)
Above Average: 20-22 (Men), 17-19 (Women)
Excellent: 22-24 (Men), 19-21 (Women)
Superior: > 24 (Men), > 21 (Women)
FFMI Results
Your Fat-Free Mass Index
FFMI Categories Comparison
| Category | Men (FFMI) | Women (FFMI) | Description |
|---|
FFMI Calculation Formula
FFMI = [Weight × (1 – Body Fat % / 100)] ÷ Height²
Where:
• Weight = Body weight in kilograms
• Body Fat % = Percentage of body fat (decimal)
• Height = Height in meters
Normalized FFMI (for height):
• Normalized FFMI = FFMI + 6.1 × (1.8 – Height in m)
Conversions:
• Pounds to kg: weight ÷ 2.20462
• Inches to meters: height × 0.0254
Example Calculation
Example: Male, 80 kg, 180 cm, 12% body fat
Weight: 80 kg
Height: 1.80 m
Body Fat: 12%
Calculation:
Lean Mass = 80 × (1 – 0.12) = 70.4 kg
FFMI = 70.4 ÷ (1.80)² = 70.4 ÷ 3.24 = 21.73
Normalized FFMI = 21.73 + 6.1 × (1.8 – 1.8) = 21.73
Result: FFMI 21.7 (Above Average)
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