Body Surface Area Calculator
BSA by Du Bois, Mosteller, Haycock and Boyd.
Dosing protocols specify which formula to use, and they disagree by a few percent. Follow your local protocol rather than picking the most convenient number.
Body surface area (Mosteller)
1.84 m²
How the Body Surface Area Calculator works
Body surface area scales with metabolic processes more closely than weight does, which is why it is the basis for chemotherapy dosing, cardiac index, and estimating burn extent. Several formulas exist and they disagree by a few percent, so clinical protocols usually specify which one to use.
Not medical advice. This calculator gives a general estimate, not medical advice. It cannot account for your individual health, medical history, or medication. Talk to a qualified healthcare professional before acting on any result.
Frequently asked questions
What is the Mosteller formula?
BSA in m² = the square root of (height in cm × weight in kg ÷ 3600). It is the most widely used because it is simple enough to do on a calculator at the bedside and agrees closely with the older, more complex equations.
Which BSA formula should I use?
Follow whatever your local protocol specifies — the choice matters because doses are calculated from it. Mosteller is the most common default. Du Bois is the historic standard from 1916 and can underestimate in obesity. Haycock was derived with children included.
Why is chemotherapy dosed by body surface area?
The practice dates from early trials where BSA correlated better than weight with the doses animals tolerated. It remains standard, though it is well recognised as an imperfect proxy: it ignores body composition, organ function and genetics, and there is ongoing work on better dosing models.
What is a normal body surface area?
Roughly 1.7 m² for an average adult, with typical values around 1.6 m² for women and 1.9 m² for men. A newborn is about 0.25 m². The figure is only meaningful next to the dose or index it is being used for.