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Weight that is not fat, estimated for a man from weight and height: 0.407 times weight plus 0.267 times height minus 19.2.
In Swedish: Fettfri massa, män (Boer)
LBM
Weight that is not fat, estimated for a man from weight and height: 0.407 times weight plus 0.267 times height minus 19.2 (Boer, 1984).
LBM=61.42
LBM equals ((0.407 times 80) plus (0.267 times 180)) minus 19.2, equals (32.56 plus 48.06) minus 19.2, equals 80.62 minus 19.2, equals 61.42
You are given
Round to 1 decimal.
Source: Boer P (1984). Estimated lean body mass as an index for normalization of body fluid volumes in humans. American Journal of Physiology 247(4 Pt 2), F632–F636. (coefficients read in Caruso D, De Santis D, Rivosecchi F, et al. (2018). Lean body weight-tailored iodinated contrast injection in obese patient: Boer versus James formula. BioMed Research International 2018, 8521893.) — checked October 19, 2026
m is the weight in kilograms, h the height in centimetres and LBM the lean body mass in kilograms: bone, muscle, organs and water, everything that is not fat. Boer fitted the coefficients in 1984 to normalise body fluid volumes; the source is cited under the formula, and the version for women is on its own page.
Holds when the body is of ordinary build. The equation returns the average lean mass of men with that weight and height, so a bodybuilder and a sedentary man of the same measurements get the same number, and neither is measured.
80 kg and 180 cm: LBM = 0.407 · 80 + 0.267 · 180 − 19.2 = 32.56 + 48.06 − 19.2 = 61.4 kg. The remaining 18.6 kg, 23% of the weight, is the fat mass the estimate implies.
The weight term is less than half: of each extra kilogram at the same height, the formula counts 0.407 kg as lean and the rest as fat. The height term adds 0.267 kg for every centimetre at the same weight, since a taller man of the same weight has more frame and less fat. The constant 19.2 sets the scale.
Lean body mass and body fat percentage describe the same split from two sides: fat = weight − LBM, and the percentage is fat over weight. The body fat percentage page estimates the fat from circumferences instead of from weight and height, and the two estimates agree only on average.
What is lean body mass used for?
Dosing drugs that distribute in lean tissue, scaling physiological measures, and setting a protein
intake per kilogram of lean mass. Boer wrote it for body fluid volumes.
Are there other formulas?
James (1976) and Hume (1966) give lean mass from the same two inputs with other coefficients, and
differ from Boer by a kilogram or two over the usual range.
Where is it calculated with the other ratios?
In the body measurements calculator, with surface area and the
waist ratios.
| Solve for | Rearranged | With the numbers | Comes to |
|---|---|---|---|
| m | LBM | 61.4 | 80 |
| h | LBM | 61.4 | 180 |
| LBM | 0.407m | 0.407·80 | 61.4 |
Last reviewed October 20, 2026 ·How pages are reviewed
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