Body Surface Area (Mosteller)

The Mosteller formula gives an estimated body surface area (BSA) from a person’s height and mass. It works because BSA tends to scale with overall body size in a way that is roughly proportional to the square root of height times weight, and the constant 3600 is a unit-adjustment factor for centimetres and kilograms. In medicine, BSA is useful because many physiological quantities, especially drug doses and metabolic rates, relate more closely to body surface area than to body weight alone.

Use this formula when you need a quick BSA estimate for medical or fitness-related calculations, such as dosing certain medications, assessing burn severity, or comparing metabolic demand between people of different sizes. It is most appropriate when height is in centimetres and mass is in kilograms.

• Using inches or pounds instead of centimetres and kilograms without converting first
• Forgetting that the square root applies to the entire fraction, not just to one variable
• Reporting the result in cm² instead of m²