Body Surface Area (BSA) Calculator
Calculate body surface area with Mosteller, Du Bois and Haycock.
Body surface area (BSA) is used in medicine to dose some drugs and assess metabolic needs. The Mosteller formula is the most common; Du Bois and Haycock are shown for comparison. An estimate for reference, not a prescription. Runs in your browser.
Results are general estimates for information only, not medical advice — consult a qualified professional for health decisions. See how we build our calculators.
Calculate body surface area (BSA) from your height and weight. BSA is used in medicine to dose some medications and assess metabolic needs. The Mosteller formula is the most widely used; the Du Bois and Haycock results are shown for comparison. An estimate for reference, not a prescription. Runs in your browser.
How to use the Body Surface Area Calculator
- Pick metric or imperial.
- Enter your weight and height.
- Read your BSA in m² from each formula.
Frequently asked questions
What is body surface area used for?
BSA correlates with metabolic rate and organ size, so clinicians use it to calculate doses for some drugs (notably chemotherapy) and to index measurements like cardiac output.
Which BSA formula is best?
Mosteller is the most common because it's simple and accurate; Du Bois is the classic original; Haycock works well across children and adults. They usually agree closely.