The lean body mass (LBM) calculator calculates your estimated lean body mass and body fat percentage based on your age, gender, weight and height using 3 different formulas (4 if you are 14 years or younger).

A good lean body mass should be between 70 and 90% to be considered healthy.

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Lean Body Mass Formula's for Adults

Over the years multiple empirical formulas have been created to estimate lean body mass. The most accurate one is considered to be the Boer formula. All formula's below require weight in kilogram and height in centimeter. The resulting number is in kilogram.

Boer formula:


eLBM = 0.407 x Weight [kg] + 0.267 x Height [cm] - 19.2


eLBM = 0.252 x Weight [kg] + 0.473 x Height [cm] - 48.3

James formula:


eLBM = 1.1 x Weight [kg] - 128 x (Weight [kg] / Height [cm])2


eLBM = 1.07 x Weight [kg] - 148 x (Weight [kg] / Height [cm])2

Hume formula:


eLBM = 0.32810 x Weight [kg] + 0.33929 x Height [cm] - 29.5336


eLBM = 0.29569 x Weight [kg] + 0.41813 x Height [cm] - 43.2933

Lean Body Mass Formula for Children

Peters formula:

This formula is only considered accurate for children less than or equal to 14 years of age.

3.8 x (0.0215 x Weight [kg]0.6469 x Height [cm]0.7236)

Note: 1 kilogram (kg) = 2.2 pounds (lb), 1 meter = 3.28084 feet


1. Boer, P Estimated lean body mass as an index for normalization of body fluid volumes in humans. Am J Physiol 1984; 247: F632-5

2. James, W Research on obesity: a report of the DHSS/MRC group. HMSO 1976

3. Hume, R Prediction of lean body mass from height and weight J Clin Pathol. 1966 Jul; 19(4): 389–391

4. A. M. Peters, H. L. R. Snelling, D. M. Glass, N. J. Bird Estimation of lean body mass in children British Journal of Anaesthesia 106(5): 719-23 (2011)