Question 1

What is body surface area used for?

Accepted Answer

BSA is used to calculate doses for chemotherapy and certain other medications, to index measurements like cardiac output (giving cardiac index), and as an input in some clinical equations. It’s considered a better proxy than weight alone for how a drug distributes through the body in many contexts.

Question 2

What’s the difference between the Du Bois and Mosteller formulas?

Accepted Answer

Du Bois & Du Bois (1916) was derived from a small direct-measurement study and has been the traditional reference formula for decades. Mosteller (1987) is a simpler formula that’s easier to compute by hand and tends to agree closely with Du Bois across most adult body sizes — it’s now the more commonly used formula in clinical practice and EHR systems.

Question 3

How much do the two formulas differ in practice?

Accepted Answer

For most adults, the two formulas typically agree within a few hundredths of a square meter. Differences tend to be larger at the extremes of height and weight. This calculator shows both results so you can compare.

Question 4

What is an average adult BSA?

Accepted Answer

Roughly 1.7 m² for an average-sized adult, though this varies with height and weight — a common rough reference used in some drug labeling defaults to 1.73 m² for standardization purposes.

Question 5

Can I use this to calculate my chemotherapy dose?

Accepted Answer

No — use this to understand the BSA calculation, but actual chemotherapy dosing must be calculated and verified by an oncology pharmacist or prescriber using the specific protocol, dose caps, and rounding rules for that regimen.

Body Surface Area (BSA) Calculator

How BSA is calculated

Common questions