What it means
Body surface area (BSA) is the total surface area of your body, in square metres. It tracks metabolic rate better than weight, which is why medicine uses it for drug dosing, cardiac index and burn assessment. Eight published formulas estimate it from your height and weight, and they agree closely — a narrow, reassuring range.
Which formula?
- Mosteller — the clinical default: √(height·weight / 3600).
- Du Bois & Du Bois (1916) — the historical classic, still widely cited.
- Haycock, Gehan–George, Boyd — fitted to broader or younger samples.
Because they agree so closely, the honest answer is the range, not one formula.
FAQ
What is the most common BSA formula?
Mosteller — √(height·weight/3600) — is the clinical default because it is simple and accurate. Du Bois (1916) is the historical classic. On typical adults they agree within a few hundredths of a m².
What is body surface area used for?
BSA is used to dose chemotherapy and other drugs, to index cardiac output (cardiac index), to estimate burns, and in dialysis. It relates better to metabolic rate than weight alone.
Why do BSA formulas give slightly different numbers?
Each was fitted to a different population and era. The good news is they agree closely — the spread is usually under 0.1 m², which is why a range is reassuring rather than confusing.
What is a normal body surface area?
Average adult BSA is roughly 1.7 m² for women and 1.9 m² for men, but it scales with height and weight — your own range is what matters.