Which BSA formula should I use?

Du Bois & Du Bois (1916) is the historical standard. Mosteller (1987) is the simplest and most widely used clinically because it is just the square root of height in cm times weight in kg divided by 3600. Haycock works well across children and adults. All three are shown here.

What is body surface area used for?

BSA is used to scale many clinical values to body size — most commonly chemotherapy and other drug doses, cardiac index, and burn assessment. It often tracks physiology better than weight alone.

Is my data sent anywhere?

No. Every calculation runs locally in your browser and nothing is uploaded.

Body Surface Area Calculator

Body surface area (BSA) calculator

Body surface area estimates the total external area of the body in square metres and is widely used to scale drug doses and other clinical values to body size.

This calculator gives you all three common formulas at once:

Du Bois & Du Bois (1916): 0.007184 × height(cm)^0.725 × weight(kg)^0.425
Mosteller (1987): √(height(cm) × weight(kg) ÷ 3600)
Haycock (1978): 0.024265 × height(cm)^0.3964 × weight(kg)^0.5378

Enter your height and weight in metric or imperial units and the results update instantly — entirely in your browser, with nothing uploaded.