Formulas
- Mosteller: BSA (m²) = square root of (height in cm × weight in kg ÷ 3600) [1]. The simplest and most widely used formula in oncology.
- DuBois: 0.007184 × weight0.425 × height0.725; usually a few hundredths lower than Mosteller.
- Ideal body weight (Devine): 50 kg (men) or 45.5 kg (women) plus 2.3 kg per inch over 5 feet; adjusted body weight = ideal weight + 0.4 × (actual − ideal weight).
Dosing in obese patients
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The ASCO guideline (2021) recommends full weight-based doses using actual body weight for cytotoxic drugs in obese patients, especially when treatment is curative; capping BSA at 2 m² is not routinely recommended [2]. If toxicity occurs, reduce doses as for non-obese patients [2]. Usual exceptions are given in the label (for example the 2 mg vincristine cap, and carboplatin, which is dosed with the Calvert formula).
Many centres round the total dose by up to about 5% to match vial sizes; this has no clinical effect but should follow local policy.
Common questions
Which weight should be used for BSA?
Actual weight on the day of treatment [2]. If weight changes by more than about 10% during treatment, recalculate the dose.
Why do Mosteller and DuBois give slightly different results?
They were derived from different data; the difference is usually below 5%. In practice, use one formula consistently [1].
References
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Numbers in the text, such as [1], refer to these sources. Sources with a “Study card” button are summarised in the site’s evidence library.
- 1
- 2
This page is based on reputable scientific sources and was last updated on 27 October 2026. The content of this website is for educational and informational purposes only and does not replace consultation, diagnosis or treatment by a specialist physician. Consult your treating physician about any treatment decision.
Printed from the website; the full and up-to-date version: https://drdabiri.com/en/tools/bsa-calculator/