Body Surface Area (BSA) Calculator
Enter height in cm and weight in kg to compute body surface area with the Mosteller, Du Bois or Haycock formulas — BSA in m² is widely used to dose chemotherapy and to express cardiac index; the calculator can show all three formulas side by side for comparison.
For self-reference only. This is not a medical diagnosis or treatment advice — dosing decisions must follow clinical guidelines and your doctor.
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What is it
Body surface area (BSA) estimates the total skin area of the body in square metres. Because it scales with both height and weight, it is often a better basis than body weight alone for drug dosing (e.g. chemotherapy) and for normalising heart-output or metabolic comparisons.
Notes & fun facts
A patient who always seemed small on the scales turns out to have a normal BSA once height is included — nurses and oncologists have relied on this for decades because BSA reflects true size better than weight alone.
Origin & history
Using body surface area to guide clinical dosing is over a century old: in 1916 Du Bois published an early formula based on a handful of human measurements, and medicine has since commonly dosed drugs such as chemotherapy by BSA. In 1987 Mosteller proposed a simple square-root formula that spread widely because it is easy to compute, and it remains a common bedside estimate today.
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