Body Composition
As of 2026-04-24
How Lean Body Mass Calculator works
Methodology for the Lean Body Mass Calculator: formulas, coefficients, data sources, assumptions, and known limitations.
Scope
Estimates lean body mass from height and weight using four classic formulas (Boer, James, Hume, Peters).
Formula
Boer (M) = 0.407*W + 0.267*H - 19.2. Boer (F) = 0.252*W + 0.473*H - 48.3. James and Hume use different polynomial forms.
Coefficients
| Parameter | Value | Note |
|---|---|---|
| Boer W coef (M) | 0.407 | |
| Boer H coef (M) | 0.267 | |
| Boer intercept (M) | -19.2 |
Data sources
- Boer P. Estimated lean body mass as an index for normalization of body fluid volumes in humans. Am J Physiol. 1984;247(4):F632-F636. — PMID 6496691.
- Hume R. Prediction of lean body mass from height and weight. J Clin Pathol. 1966;19(4):389-391. — PMID 5929341.
- Peters AM, Snelling HL, Glass DM, Bird NJ. Estimation of lean body mass in children. Br J Anaesth. 2011;106(5):719-723. — PMID 21317249. Peters formula reference paper.
- James WPT. Research on obesity: a report of the DHSS/MRC group. London: Her Majesty's Stationery Office, 1976. — UK government report; no stable peer-reviewed URL exists, but the James LBM formulas are routinely cited from this HMSO publication.
Assumptions
- Height and weight measured, not estimated.
Approximation range
Four-formula spread is typically 2–4 kg for a given person; display the range, not a single formula's output.
Limitations
- Formulas were fit on general-population data; heavily muscled athletes are systematically under-predicted.
- Do not use LBM formulas to validate a body-fat measurement — the two would be circular.
Reproducibility
Male, 85 kg, 180 cm. Boer: 0.407*85 + 0.267*180 - 19.2 = 63.6 kg.
Change log
- 2026-04-24: methodology page first published.
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