Body surface area (Mosteller)
- Category: General
- Version: v1.0.1
- Reviewed: Reviewed 6 Sep 2026
- Validation: Validation pending
BSA in square metres is the square root of (height in cm × weight in kg ÷ 3600). There are no age or sex terms. Compute in full floating point and round once at display.
BSA is a body-size scalar consumed by downstream calculations such as mg/m² dosing and cardiac index, so it carries no bands. Mosteller was validated against the Du Bois formula, itself fit to 9 adults in 1916, rather than against direct measurement. Agreement with pediatric-fit estimators widens at the extremes (neonates, severe obesity), so any platform indexing by BSA should record which formula it uses. The main failure mode is unit transposition (lb↔kg, in↔cm): because BSA scales as a square root, a swapped unit yields a wrong-but-plausible number the formula cannot self-detect.
References
- Mosteller RD. Simplified calculation of body-surface area. N Engl J Med. 1987;317(17):1098.Primary source: BSA = sqrt(height·weight/3600) (metric) and the sqrt(height·weight/3131) imperial variant.PMID 3657876DOI 10.1056/NEJM198710223171717
- Du Bois D, Du Bois EF. A formula to estimate the approximate surface area if height and weight be known. Arch Intern Med. 1916;17(6):863–871. (Reprinted: Nutrition. 1989;5(5):303–311.)The comparator/gold-standard formula the Mosteller estimator was designed to approximate; cited for the limitations discussion, not implemented.PMID 2520314
- Evidencio — Body surface area (Mosteller formula), model 518.Secondary confirmation of the metric formula BSA(m²) = sqrt(height_cm × weight_kg / 3600) and the Mosteller 1987 citation.Source
- Omnicalculator — BSA Calculator (Body Surface Area).Secondary confirmation and the 170 cm / 60 kg worked example (Example D) reproduced as an external check.Source
Reproduction rights
Freely reproducible.The Mosteller estimator is a single mathematical expression (a square root of a product over the constant 3600); formulas, constants, and the ½-power are facts/algorithms, not copyrightable expression, and there is no proprietary scale wording (research §"IP status").
Independent clinical validation: pending
Two independent clinical validators will be named here once review is complete.
- 2026-09-03v1.0.0Initial releaseInitial published text.
- 2026-09-06v1.0.1ClarificationAdded a one-line description for the catalogue card. No rule, threshold or reference changed.
Other general scores
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- Corrected QT intervalHeart-rate-corrected QT interval by Bazett and Fridericia
- FOUR scoreComa assessment that stays complete in an intubated patient
- Ideal body weightIdeal body weight from height, by four published methods side by side
- Pediatric Glasgow Coma ScaleAge-adapted Glasgow Coma Scale for infants and children
Important. For use by qualified health professionals as an informational and educational aid. It supports clinical judgment and does not replace it. Verify every result independently before making a clinical decision. This is not a medical device.