Body Surface Area (BSA) is an estimate of the total surface area of the body, used primarily for medication dosing — particularly chemotherapy — and clinical assessments. Like BMI, it requires accurate height and weight measurements.
Open the Body Surface Area Calculator CalculatorStand barefoot with your back flat against a wall, feet together and heels touching the wall.
Look straight ahead — your chin should be level, not tilted up or down.
Place a flat book on top of your head, pressing it gently against the wall.
Mark the wall at the bottom of the book and measure from the floor to the mark.
Weigh yourself first thing in the morning, after using the bathroom, in minimal clothing.
Enter your height and weight into the BSA calculator, selecting your preferred unit system.
These ranges are educational references only and do not replace professional medical evaluation.
Healio360 saves BSA results to your Health History. Because BSA is used for clinical dosing, having a record of previous calculations can be useful when discussing treatments with a healthcare team.
View Health IntelligenceWhat is body surface area used for?
BSA is commonly used to calculate drug doses — particularly in oncology (chemotherapy) — where dosing based on body surface area is more precise than body weight alone.
Is there a normal BSA?
There is no single "normal" BSA — it varies with height and weight. Average BSA for an adult is approximately 1.7–1.9 m². It is used as a dosing reference, not a health indicator.
Does BSA change over time?
Yes — BSA changes if your height or weight changes. This is why accurate, up-to-date measurements are important, especially for clinical use.