What body surface area is
Body surface area (BSA) estimates the total external area of the body in square metres. It scales with both weight and height, and in clinical settings it is often a better basis for dosing and physiological comparison than weight alone because it tracks metabolic size more closely.
This calculator reports the Du Bois value as the headline result and the Mosteller value alongside it, so you can see both classic estimates at once.
Du Bois vs. Mosteller
The Du Bois formula, published in 1916, is the long-standing reference and uses a power-law combination of weight and height. The Mosteller formula is a simpler square-root expression that is easy to compute by hand and is popular in chemotherapy dosing.
The bar chart places the two estimates side by side. For most people they agree to within a few percent; noticeable gaps tend to appear only at the extremes of body size.
Where BSA is used
BSA appears in several clinical and physiological calculations:
- Dosing of certain drugs, including many chemotherapy agents.
- Indexing cardiac output and other measures to body size.
- Estimating burn extent and fluid requirements.
- Comparing organ function such as kidney filtration across body sizes.
Health note
These formulas are population estimates and may not reflect any individual exactly. They are provided for general information and education, not for self-directed dosing. Any clinical use of BSA should be carried out by a qualified healthcare professional.
Formula
Du Bois: 0.007184·kg^0.425·cm^0.725; Mosteller: √(cm·kg / 3600)Frequently asked questions
- Which formula is more accurate?
- Both are widely used. Mosteller is simpler and easy to compute by hand; Du Bois is the classic reference. They usually agree closely.