0 m² (Mosteller)
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Du Bois & Du Bois
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Haycock
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Gehan & George
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Average of methods
Body surface area (BSA) is used in medicine to size drug doses (especially chemotherapy), IV fluids and cardiac index. The Mosteller formula — √(height·weight ÷ 3600) — is the most widely used; the others are shown for comparison. An average adult is roughly 1.7 m².
Frequently Asked Questions
What is body surface area used for?
BSA estimates the total external area of the body in square metres. Clinicians use it to calculate drug doses (notably chemotherapy), intravenous fluid needs, glomerular filtration rate and cardiac index, because these scale better with surface area than with body weight alone.
Which BSA formula should I use?
The Mosteller formula is the simplest and most commonly used: BSA (m²) = √(height in cm × weight in kg ÷ 3600). Du Bois, Haycock and Gehan & George give very similar results; we show all four plus their average.
What is a normal BSA?
An average adult is about 1.6–1.9 m² (roughly 1.7 m² is often used as a reference). Children are lower, and BSA increases with both height and weight.
Calculate your body surface area (BSA) in square metres using the Mosteller, Du Bois, Haycock and Gehan & George formulas — used for medical dosing.