Health & Fitness
Lean Body Mass Calculator
Estimate lean body mass from total weight and body fat percentage.
The result shows your estimated lean body mass in kilograms, with the estimated fat mass in brackets, so you can see how much of your total weight is lean tissue rather than fat.
Formula
Lean body mass equals total weight multiplied by one minus body fat percentage.
How it works
Fat mass is weight times body-fat fraction, and everything else — muscle, bone, water and organs — is the remainder. The result is only as good as the body-fat figure you enter.
Worked example
For example, a weight of 70 kg with 20% body fat gives a fat mass of 70 × 0.20 = 14.0 kg and a lean body mass of 70 × (1 − 0.20) = 56.0 kg.
FAQs
Is lean mass the same as muscle?
No. Muscle is part of lean mass, along with bone, water and organs.
Why track it?
It shows whether weight change is mostly fat or mostly lean tissue.
How accurate is it?
It inherits the error of the body-fat estimate.
General information only, not medical advice.
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