BSA Calculator – Body Surface Area

Body Surface Area is measured in square meters (m²) and is considered a more accurate indicator of metabolic mass than body weight alone because it is less affected by abnormal adipose tissue accumulation. The calculator utilizes several clinically validated equations based on height (H in centimeters or meters) and weight (W in kilograms). The Mosteller formula is prized for its mathematical simplicity: BSA = sqrt((Height in cm * Weight in kg) / 3600). Meanwhile, the Du Bois formula uses fractional exponents: BSA = 0.007184 * W^0.425 * H^0.725. Other formulas such as Haycock, Gehan-George, and Fujimoto apply unique coefficients derived from empirical anthropometric studies to tailor estimates for specific populations.

Let us walk through calculating the BSA for an adult patient with a height of 5 feet 4 inches (162.56 cm) and a weight of 163 pounds (73.94 kg) using the popular Mosteller formula. First, multiply the height in centimeters by the weight in kilograms: 162.56 * 73.94 = 12,020.08. Next, divide that product by the constant 3600: 12,020.08 / 3600 = 3.3389. Finally, calculate the square root of that result: sqrt(3.3389) = 1.83 m². Thus, the patient's estimated Body Surface Area is approximately 1.83 square meters.

When utilizing a BSA calculator for clinical dosing, always verify which formula your institution or protocol requires, as slight variations exist between Mosteller and Du Bois outputs. Ensure accurate conversion of imperial measurements to metric units if entering data manually, converting pounds to kilograms by dividing by 2.2046. Additionally, remember that BSA is an estimation model rather than a direct physical measurement; always correlate calculated values with clinical observations and patient status.