Body Surface Area Calculator

Body Surface Area (BSA) is a crucial measurement in medicine, used to determine correct dosages for chemotherapy, evaluate burns, and assess cardiac output. Unlike simple BMI, BSA considers both height and weight to estimate the total surface area of the human body. Our calculator implements the three most trusted formulas: Mosteller (simplified and widely used), DuBois & DuBois (the historical standard), and Haycock (often used for pediatric and intensive care). BSA is expressed in square meters (m²).

The Mosteller formula takes the square root of (height in cm × weight in kg / 3600), giving a fast, accurate result. The DuBois formula (0.007184 × height^0.725 × weight^0.425) has been the reference for decades, while Haycock (0.024265 × height^0.3964 × weight^0.5378) is preferred for infants and critical care. By providing all three, you can compare and use the value most accepted in your clinical setting. For average adults, BSA typically ranges from 1.6 to 2.0 m².

Why is BSA so important? Many chemotherapy drugs are dosed per square meter to reduce toxicity variation. Fluid resuscitation for burn victims relies on BSA to estimate total body surface area burned. Even renal function measurements (e.g., glomerular filtration rate) are often normalized to 1.73 m². This tool is intended for educational and planning purposes — always consult a healthcare professional for actual treatment decisions. The calculator is fully responsive, works offline after loading, and respects your privacy: no data is stored or transmitted. Use it as often as needed, and share it with colleagues or students who need quick, reliable BSA estimates.