Lean Body Mass Calculator
Estimate lean body mass from height, weight and sex by the Boer, James and Hume formulas, with each as a share of body weight.
Lean body mass is body weight minus fat, estimated here from height, weight and sex. The Boer formula for men is 0.407 x weight in kg + 0.267 x height in cm - 19.2. For a man 178 cm tall weighing 80 kg that gives 60.9 kg, or 76.1% of body weight. The James formula gives 62.1 kg and the Hume formula 57.1 kg.
This calculator is for general education only. It is not medical advice, a diagnosis or a measurement of your body composition. The results are estimates from height, weight and sex by the three formulas credited below, which were fitted to adults and give different answers, more so at high weight for height, where James falls away. Do not use them to set a medicine dose, a diet or a training plan. If you have questions about your weight, body composition or health, talk to a doctor, dietitian or another qualified health professional.
Lean body mass (Boer)
60.9 kg
- Boer (1984)
- 60.9 kg (76.1%)
- James (1976)
- 62.1 kg (77.7%)
- Hume (1966)
- 57.1 kg (71.4%)
Estimates from height and weight, with the share of body weight in brackets. They do not measure body composition. James is shown as not valid where its result is not above zero or not below body weight.
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About the Lean Body Mass Calculator
Lean body mass is everything in the body that is not fat: muscle, bone, organs and water. These formulas, fitted on adults, estimate it from height and weight, with separate equations for men and women. Boer (1984): men 0.407 x weight + 0.267 x height - 19.2, women 0.252 x weight + 0.473 x height - 48.3, with weight in kg and height in cm. James (1976): men 1.1 x weight - 128 x (weight / height) squared, women 1.07 x weight - 148 x (weight / height) squared. Hume (1966): men 0.32810 x weight + 0.33929 x height - 29.5336, women 0.29569 x weight + 0.41813 x height - 43.2933. For a man of 70 in and 180 lb (177.8 cm and 81.6 kg at 2.54 cm to the inch and 0.45359237 kg to the pound), Boer gives 61.5 kg, or 135.6 lb, 75.3% of body weight. James subtracts a term that grows with weight for height, so its result falls at high weights: for a woman of 150 cm and 200 kg it is below zero, and the calculator shows it as not valid; Boer gives 73.1 kg.
Frequently asked questions
How do I calculate lean body mass?+
Pick a formula and use the equation for your sex. With Boer for a man, multiply weight in kg by 0.407 and height in cm by 0.267, add them, and subtract 19.2. For 178 cm and 80 kg that is 60.9 kg. The calculator works all three formulas at once.
Why do the three formulas give different answers?+
Each comes from a different study, so the equations differ. For the same person they can differ by several kilograms: a man of 178 cm and 80 kg gets 57.1 kg (Hume) to 62.1 kg (James). James also drops away at high weight for height, so the page shows the results side by side and marks any result that cannot be right, such as a negative value, as not valid.
Is lean body mass the same as muscle mass?+
No. Lean body mass includes muscle, bone, organs and body water, so it is always larger than muscle mass alone. These formulas estimate the whole lean total, not muscle.
How accurate is a lean body mass formula?+
It is an estimate for an average person with your height, weight and sex. It cannot see how much of your weight is muscle or fat, so athletes and people with a lot of body fat can differ from it. A body composition scan, such as DXA, estimates it by a different method.
Formulas: Boer P, Estimated lean body mass as an index for normalization of body fluid volumes in humans, Am J Physiol 1984;247:F632-F636. James WPT, Research on obesity (DHSS/MRC group report), HMSO, London, 1976. Hume R, Prediction of lean body mass from height and weight, J Clin Pathol 1966;19:389-391.
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