What is Body Surface Area?
**Body Surface Area (BSA)** is the measured or calculated surface of a human body. In many clinical situations, BSA is a better indicator of metabolic mass than body weight because it is less affected by abnormal adipose mass.
It has been the "Gold Standard" for chemotherapy dosing since 1950 to minimize the variation in drug distribution between patients.
The 4 Formulas Compared
Mosteller (1987)
The modern standard. It is mathematically simpler and just as accurate as older formulas.
√ ( (Height(cm) × Weight(kg)) / 3600 )Du Bois (1916)
The historical benchmark. Often specifically required for obese patients in some protocols.
Haycock (1978)
Preferred in Pediatrics, especially for infants, as it handles lower surface areas better.
Gehan-George (1970)
Originally developed for cancer chemotherapy dosing.
Clinical Applications
Chemotherapy Dosing
Antineoplastic agents have a narrow therapeutic index. Dosing by BSA helps normalize drug exposure across individuals of different sizes.
Cardiac Index (CI)
Used to relate heart performance to the size of the individual.
Formula: CI = Cardiac Output / BSA.
Allows comparison of heart function between a large person and a small person.
Frequently Asked Questions
What is a "normal" BSA?
- Average Man: 1.9 m²
- Average Woman: 1.6 m²
- Neonate: ~0.25 m²
- 2 Year Old: ~0.5 m²
Which formula should I use?
Tools & Data Verified by the EverydayCalculators Medical Research Team.
Last updated: December 2025.