How this calculator works
Boer's 1984 equations estimate lean mass in adults from sex, weight and height. They were developed for fluid-volume normalisation in healthy and obese adults. They are not suitable for amputees, elite athletes, oedema or pregnancy. A calculated lean mass at or above total weight is rejected. Lean mass includes water, organs and bone as well as muscle. The result is an estimate for information only and is not medical advice.
Formula
Male LBM (kg) = 0.407w + 0.267h - 19.2; female LBM = 0.252w + 0.473h - 48.3, with weight w in kg and height h in cm. Lean fraction = LBM / weight.
Worked example
At 80 kg and 180 cm, the male estimate is 61.42 kg, or 76.8% lean mass. A female at 60 kg and 165 cm has 44.865 kg estimated lean mass.
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Frequently asked questions
Is lean mass the same as muscle?
No. Lean mass also includes organs, water, bone and other non-fat tissue.
Why reject lean mass above weight?
That result is physically inconsistent and indicates the equation is unsuitable for those inputs.
Can I use this for an athlete or during pregnancy?
No. The Boer equations were developed for healthy and obese adults and are not suitable for elite athletes, oedema or pregnancy.