Muscle Mass Calculator

This estimates total-body skeletal muscle mass using the two anthropometric equations Lee and colleagues published in 2000 against whole-body MRI. The caliper tab takes height, weight, age, sex, ethnicity and the arm, thigh and calf circumferences with a skinfold at each; the second tab drops the caliper and works from height, weight, age and sex alone at a wider error. You get the muscle mass in kilograms and pounds, its share of body weight as a skeletal muscle index, and the 95 percent band the equation's standard error implies. Skeletal muscle is not lean body mass, which also holds bone, organs, blood and water and is roughly twice as large, so the two figures cannot be compared.

Calculator Type
Units

The more accurate of the two, standard error 2.2 kg. Needs a skinfold caliper and a tape: arm, thigh and calf, each with the skinfold at the same place.

The equations carry one term for sex, fitted on male and female subjects.
Lee fitted a separate constant for each of these three groups and the site cannot offer a group the study did not measure. If none of them describes you, take the White or Hispanic setting and widen the error band.
Relaxed arm hanging at the side, measured midway between the tip of the shoulder and the point of the elbow.
Always millimetres, which is what every caliper reads. Vertical fold at the back of the arm, at the same height as the girth.
Midway between the inguinal crease and the top of the kneecap, standing with the weight on the other leg.
The widest part of the calf, standing with the weight spread evenly.
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Units

The same study's second model, for when there is no caliper. Wider error, standard error 2.8 kg, because nothing in it can tell a heavy muscular body from a heavy fat one.

The equations carry one term for sex, fitted on male and female subjects.
Lee fitted a separate constant for each of these three groups and the site cannot offer a group the study did not measure. If none of them describes you, take the White or Hispanic setting and widen the error band.
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BMI Calculator Body Fat Calculator Lean Body Mass Calculator