BSA Calculator
Body Surface Area from weight and height — Mosteller and Du Bois formulas.
The BSA Calculator estimates Body Surface Area — the total area of your skin — from weight and height using the two most common formulas: Mosteller's simple square-root equation and the classic Du Bois formula used in clinical pharmacology.
BSA is a standard scaling measure in medicine: many medications, especially chemotherapy agents and some cardiac drugs, are dosed per square meter of body surface area rather than per kilogram, because skin and organ functions scale more closely with BSA. Physiology and exercise science also use it to normalize cardiac output and metabolic measures.
This tool is strictly educational — clinical dosing decisions belong to professionals with the full patient context. The two formulas agree within a few percent for average body sizes. Runs entirely in your browser.
Body surface area
1.82 m²
Mosteller formula
Du Bois estimate
1.81 m²
classic clinical formula
BSA is used to scale some medications, chemotherapy doses and physiological measures. Educational estimate — clinical dosing must come from a professional.
How to use the BSA Calculator
- Enter your weight in kilograms.
- Enter your height in centimeters.
- Read your BSA from the Mosteller formula.
- Check the Du Bois estimate alongside it.
- Use the average of the two for general purposes.
Frequently asked questions
What is the Mosteller formula?
BSA (m²) = √(weight(kg) × height(cm) ÷ 3600). It was developed in the 1980s as a simpler, more accurate alternative to earlier formulas and is now the most commonly used in clinical practice.
Why is BSA used for drug dosing?
Metabolic and physiological processes scale more closely with surface area than with weight alone, so BSA-based dosing improves safety and efficacy for certain drugs. Always follow clinical guidance — this calculator is for education.
What is a normal BSA?
Typical adult values range from about 1.5 to 2.2 m² — roughly 1.7 m² for average-sized men and 1.6 m² for average-sized women. BSA correlates with both height and weight.
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