How body surface area is calculated
Body surface area (BSA) estimates the total external area of the body in square metres. It is widely used in medicine, for example to calculate drug doses and assess burns, because it tracks body size better than weight alone. This calculator uses the Mosteller formula, the most common method.
The formula
Mosteller BSA = the square root of (height in cm x weight in kg / 3600).
Worked example
A person 180 cm tall weighing 80 kg has a BSA of about 2.0 square metres.
Frequently asked questions
What is body surface area used for?
Mainly in medicine, to calculate drug doses (especially chemotherapy), assess burn extent, and index measurements to body size.
Which BSA formula is this?
The Mosteller formula, the most widely used because it is simple and accurate: the square root of height times weight divided by 3600.
Which formula is this?
The Mosteller formula, chosen for its simplicity and accuracy. Other formulas (Du Bois, Haycock) give very similar results.
What is a normal BSA?
Most adults fall between about 1.5 and 2.2 m², with 1.7 m² a common average.
Can I use it for drug dosing?
No. This is an educational estimate. Real dosing must be done by a qualified professional.