Body Surface Area (BSA) Calculator
Body Surface Area (BSA) is a measurement used in many medical calculations, including drug dosing, burn assessment, and physiological norms. Calculate your BSA using three widely accepted formulas from your weight and height.
Body surface area is an important clinical parameter used more frequently than body weight for many medical calculations. Chemotherapy dosing, fluid requirements, cardiac output indices, and renal function assessments all commonly use BSA. The average adult BSA is approximately 1.7 m² for women and 1.9 m² for men.
The Mosteller formula is the simplest and most widely used: BSA = sqrt((height x weight) / 3600). The DuBois formula (1916) was historically the first and remains a reference standard. The Haycock formula was specifically developed with pediatric patients in mind and is often used for children.
All three formulas typically agree within 5% for adults of normal body composition. For obese individuals or children, the Haycock formula may be more appropriate. In clinical practice, BSA-based dosing helps normalize drug doses across patients of different sizes, providing more consistent therapeutic drug levels than weight-based dosing alone.