Body Surface Area (BSA) Calculator
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Shop Withings Body Smart ScaleAbout Body Surface Area (BSA) Calculator
The Body Surface Area (BSA) Calculator estimates the total external surface area of the human body, expressed in square meters (m²). BSA is commonly used in medicine to determine accurate drug dosages, fluid requirements, and metabolic assessments.
This tool uses the Mosteller formula for its simplicity and accuracy:
BSA (m²) = √((height(cm) × weight(kg)) / 3600).
It also compares your result with the Du Bois and Haycock formulas, which are
often applied in research and pediatric contexts. You can calculate using metric or US units — all values are
internally converted to cm and kg for consistency.
How to use this BSA calculator
- Select your preferred measurement units for height and weight.
- Enter your data and click Calculate.
- See your BSA in m², with side-by-side results for Mosteller, Du Bois, and Haycock methods.
Notes
- BSA values are used clinically for medication dosing (e.g., chemotherapy, IV fluids) and metabolic rate calculations.
- This calculator is for educational and informational purposes only and not a substitute for medical advice.
- For children, elderly, or atypical body sizes, consult medical professionals for the most appropriate formula.
FAQ
- Which formula does this BSA calculator use? The calculator uses the Mosteller formula by default and also shows Du Bois and Haycock results for comparison.
- Why is BSA important? Body Surface Area (BSA) is used in clinical medicine to adjust medication dosages, estimate cardiac output, and assess metabolic function more accurately than weight alone.
- Can I enter height and weight in different units? Yes. You can use cm, in, or ft+in for height and kg or lb for weight — the calculator automatically converts all inputs to metric values.
- What is a normal adult BSA? The average adult BSA is approximately 1.7–1.9 m², but this varies with body size and composition.
- Do you provide BSA in square feet? No. BSA is shown in square meters (m²), which is the global medical standard for surface area calculations.
- Is this calculator suitable for children? It can give general estimates, but pediatric dosing should always follow medical guidance and may require specialized formulas.
Disclaimer
The calculators on this site are for educational and informational purposes only and are not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional before using BSA to inform clinical decisions.