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.
Frequently asked questions
- How does the Body Surface Area Calculator work?
- Compute BSA with the Du Bois formula used clinically.
- Is the Body Surface Area Calculator free to use?
- Yes. The Body Surface Area Calculator is completely free, runs entirely in your browser, and requires no account or sign-up. Your inputs never leave your device.
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