Body surface area (Mosteller / DuBois)
Body surface area from height and weight
Sources last checked: 2026-10-27
Body surface area (Mosteller / DuBois)
Body surface area from height and weight
Both formulas estimate surface area; they were not derived in severe obesity, amputation or oedema, where estimates diverge. The result is a measurement only — it says nothing about how a drug should be dosed.
What is the Body surface area (Mosteller / DuBois)?
Body surface area (BSA) is an estimate of the external surface of the body in square metres, calculated from height and weight. DuBois and DuBois derived their formula in 1916 from direct measurements in nine people; Mosteller proposed a simpler square-root form in 1987 that gives nearly identical results across the usual adult and paediatric range.
When to use it
- Indexing a measurement to body size, e.g. cardiac index, indexed valve area or GFR per 1.73 m²
- Burn and fluid formulas or study protocols that ask for BSA
- Comparing a value with reference ranges that are expressed per m²
When not to use it
- Severe obesity, amputations or marked oedema, where weight-based formulas misestimate surface area
- As a dosing instruction — this tool reports a measurement only
How it is calculated
Mosteller: BSA (m²) = √(height [cm] × weight [kg] / 3600) DuBois: BSA (m²) = 0.007184 × weight [kg]^0.425 × height [cm]^0.725
Clinical pearls and limitations
- Both formulas estimate surface area; they were not derived in severe obesity, amputation or oedema, where estimates diverge. The result is a measurement only — it says nothing about how a drug should be dosed.
- Mosteller and DuBois differ by less than about 2 % for most adults; they diverge more at very low or very high weight.
- Use measured, not estimated, height and current weight; a 5 kg error changes BSA by roughly 2–3 %.
- Mean adult BSA is about 1.7–1.9 m²; the 1.73 m² used to index GFR is a historical adult average.
- Choose the formula your local protocol or reference range was built on, so values stay comparable.
Frequently asked questions
Mosteller or DuBois — which is better?
Neither is clearly more accurate for most patients. Mosteller is simpler and widely used; DuBois is the historical reference. Consistency with the protocol in use matters more than the choice.
What is a normal body surface area?
Around 1.9 m² for adult men and 1.6–1.7 m² for adult women; a newborn is about 0.25 m².
Why is GFR expressed per 1.73 m²?
It normalises kidney function to a standard adult BSA so values can be compared across body sizes.
Evidence and guidelines
Have a follow-up question?
Medelix answers clinical questions from current guidelines and studies — every statement with its source.
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- Parkland formula (burns)Initial 24-hour crystalloid estimate in major burns
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<p><a href="https://medelix.ai/en/calculators/body-surface-area-calculator">Body surface area (Mosteller / DuBois) calculator by Medelix</a></p>For healthcare professionals and medical students. These tools support, and do not replace, clinical judgement. Always check results against the original source and your local protocols.