Body Surface Area (BSA) Calculator
Calculate body surface area with the Mosteller formula — used for cardiac index and many dose calculations.
How it works
The Mosteller formula is BSA (m²) = √(height[cm] × weight[kg] ÷ 3600). BSA is used to index cardiac output (cardiac index) and to size doses. Average adult BSA is roughly 1.7–2.0 m².
Frequently asked questions
How do you calculate body surface area?
Use the Mosteller formula: BSA (m²) = √(height in cm × weight in kg ÷ 3600).
What is a normal body surface area?
Average adult BSA is roughly 1.7–2.0 m².
Why is body surface area used?
To index measurements such as cardiac output (giving cardiac index) and to size drug and contrast doses.
Educational tool. These calculators are for study and RCIS exam preparation only — not for clinical decision-making or patient dosing. Always follow institutional protocols and verify with a qualified clinician.