Body Surface Area (BSA) Calculator

BSA is the total area of the outer surface of the body. Clinicians use it to scale things to body size, such as chemotherapy doses, cardiac index, glomerular filtration rate and burn assessment, where it tracks size better than weight alone.

Mosteller is the most common because it is simple and accurate for adults. DuBois and DuBois is the classic reference, while Haycock and Gehan-George were validated across children and adults. For typical adults the four agree within a few percent.

Mosteller BSA in square metres is the square root of height in centimetres times weight in kilograms divided by 3600. For example, 170 cm and 70 kg gives the square root of 11900/3600, which is about 1.818 m2.

Each formula was fitted to a different study population using different exponents on height and weight. The differences are usually small, so the compare table lets you see the spread and pick the one your clinician prefers.

No. This calculator is for general information and education only. It is not medical advice and must not be used to set drug doses or treatment. Always rely on a qualified clinician for any clinical decision.

No. The calculation runs entirely in your browser. Your height and weight are never uploaded or stored.