Body surface area (BSA) shows up in medicine more often than most people realize. Our BSA calculator computes it using the two most widely referenced formulas: Mosteller and Du Bois.
Why BSA matters
BSA is used to calculate medication dosages — especially chemotherapy drugs, where dosing per unit of body surface area is considered more precise than simple weight-based dosing — as well as to assess burn severity as a percentage of total body surface, and to estimate certain physiological parameters like cardiac output index.
The Mosteller formula
BSA = √((height in cm × weight in kg) / 3600)Simple, widely used in modern clinical practice thanks to its ease of calculation.
The Du Bois formula
BSA = 0.007184 × height^0.725 × weight^0.425Developed in 1916 from a small sample, still referenced in some clinical and research contexts today.
Example
A 175cm, 70kg adult comes out to about 1.84 m² by the Mosteller formula and 1.85 m² by Du Bois — the two formulas typically agree within a few percent for typical adult body proportions.
Not a substitute for clinical judgment
This tool is for informational and educational purposes only. Real medical dosing decisions should always be made by a qualified healthcare provider using validated clinical tools and the full clinical picture, not a standalone online calculator.