Nutrition & Body Composition
Lean Body Mass Calculator
Enter body weight and body fat percentage to estimate fat-free mass and fat mass in kilograms and pounds.
Your estimate
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Enter your details and calculate to see your estimate, the breakdown and what to explore next.
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assumptions
An educational estimate, not a measurement or medical advice.
Behind the numbers
How this calculator works
Fat mass = weight × body fat percentage ÷ 100. Fat-free mass = weight − fat mass.
A worked example
At 70 kg and 20% body fat, estimated fat-free mass is 56 kg and fat mass is 14 kg.