What is Body Surface Area (BSA)?

Body Surface Area (BSA) is the measured or calculated surface area of a human body. For many clinical purposes, BSA is a better indicator of metabolic mass than body weight because it is less affected by abnormal adipose tissue. In medical practice, BSA is most commonly used to calculate dosages for chemotherapy and other drugs with narrow therapeutic indices.

How to Calculate BSA?

There are several mathematical models used to estimate BSA. The most widely accepted and commonly used formula in clinical settings is the Mosteller Formula. It is favored for its simplicity and accuracy across various body types.

The Mosteller Formula is: BSA (m²) = √([Height (cm) x Weight (kg)] / 3600)

Why Use BSA Instead of BMI?

While Body Mass Index (BMI) focuses on weight relative to height to determine if a person is overweight or underweight, BSA focuses on the total area that the blood must supply and the skin must cover. Clinicians prefer BSA for drug dosing because it correlates more closely with physiological parameters like cardiac output and glomerular filtration rate (kidney function).

Frequently Asked Questions

What is the average BSA?
The average BSA for an adult man is generally considered to be 1.9 m², while for an adult woman, it is approximately 1.6 m².

Is this calculator suitable for children?
Yes, the Mosteller formula used in this calculator is validated for both adults and children, making it a versatile tool for pediatric dosing calculations.

Which formula is the most accurate?
While formulas like Du Bois and Haycock exist, studies suggest the Mosteller formula is just as accurate and much easier to calculate manually or programmatically.