Body Surface Area Calculator
Calculate body surface area (BSA) from height and weight using the Mosteller formula.
Body Surface Area
Calculation Steps
Body surface area is widely used to calculate medication doses, especially in chemotherapy and pediatrics. Always have doses verified by a qualified healthcare professional.
Understanding Body Surface Area (BSA)
Body surface area (BSA) is the measured or calculated total area of the outer surface of the human body, expressed in square metres (m²). In medicine, BSA is often a more accurate basis for dosing than body weight alone because it correlates more closely with metabolic processes such as cardiac output, blood volume, and renal function. It is especially important in chemotherapy, where many drugs are dosed in milligrams per square metre, and in pediatrics.
Typical BSA Values
| Group | Average BSA (m²) |
|---|---|
| Adult men | 1.9 |
| Adult women | 1.6 |
| Children (9 years) | 1.07 |
| Neonates | 0.25 |
How BSA Is Calculated
The Mosteller Formula
This calculator uses the Mosteller formula, which is widely favoured for its simplicity and accuracy. It takes height in centimetres and weight in kilograms and returns BSA in square metres.
BSA (m²) = √( height (cm) × weight (kg) / 3600 )
Worked Example
For a person 170 cm tall weighing 70 kg, BSA = √(170 × 70 / 3600) = √3.306 ≈ 1.82 m².
References
- Mosteller, R. D. (1987). "Simplified calculation of body-surface area." New England Journal of Medicine, 317(17), 1098.
- Du Bois, D., & Du Bois, E. F. (1916). "A formula to estimate the approximate surface area if height and weight be known." Archives of Internal Medicine, 17, 863–871.
Note: This calculator is for informational purposes only and does not replace professional medical advice. Medication dosing based on body surface area must be performed and verified by a qualified healthcare professional.