Body Surface Area Calculator
Calculate your body surface area (BSA) using the Mosteller formula. Used in medical dosing, cardiac output, and metabolic assessments.
What is Body Surface Area?
Body Surface Area (BSA) is the measured or calculated surface area of the human body, expressed in square meters (m²). BSA is widely used in medical settings for drug dosing calculations, determining cardiac output and index, assessing burn severity, and various metabolic measurements. Our free BSA calculator uses the Mosteller formula, which is the most commonly used and easiest to calculate manually.
Calculate Your Body Surface Area
Enter your height and weight to calculate BSA using the Mosteller formula
About the Mosteller Formula
BSA (m²) = √[(height(cm) × weight(kg)) / 3600]
Frequently Asked Questions
What is body surface area used for?
BSA is primarily used in medical settings for calculating appropriate drug dosages, especially for chemotherapy and other potent medications. It's also used to assess cardiac output (cardiac index), evaluate renal function, calculate fluid requirements, and assess burn severity.
Which BSA formula is most accurate?
The Mosteller formula is the most widely used because it's simple, easy to calculate, and clinically validated. Other formulas include DuBois, Haycock, Gehan and George, and Boyd. The Mosteller formula provides results within 2% of more complex formulas for most adults.
What is a normal body surface area?
Average BSA for adult women is around 1.6 m², and for adult men around 1.9 m². However, BSA varies significantly based on height and weight. Newborns have a BSA of approximately 0.25 m², while extremely tall or heavy individuals may have a BSA over 2.5 m².
Why is BSA important for drug dosing?
BSA-based dosing is more accurate than weight-based dosing because it better reflects metabolic mass and blood volume. This is especially important for chemotherapy drugs, where the therapeutic window is narrow and precise dosing is critical to balance efficacy with toxicity.