Body Surface Area Calculator
Compute BSA with the Du Bois formula used clinically.
Body surface area (Du Bois)
1.85 m²
Mosteller formula
1.84 m²
Adult average
1.7–1.9 m²
Why medicine uses BSA
Chemotherapy doses, cardiac output indexing, and burn assessments scale to body surface area rather than weight, because metabolism tracks surface better than mass. Du Bois (1916) remains the clinical standard; Mosteller's square-root version is the bedside favorite.
Estimates, by design
All BSA formulas are statistical fits from small historical samples — they differ by a few percent, which is why protocols name the formula they expect. For anything clinical, this is context, not a substitute for your care team's calculation.
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