Body Surface Area Calculator (BSA)

How it works

Body surface area estimates the total skin area of a body, in square metres, from height and weight. This calculator uses the Mosteller formula — √(height in cm × weight in kg ÷ 3600) — the most widely used because it is simple enough to do by hand. BSA exists because some physiological quantities scale with surface rather than with mass. Metabolic rate, heat exchange and, above all, chemotherapy dosing correlate better with area than with weight, which is why oncology prescriptions are written in milligrams per square metre. Typical adult values run about 1.6 to 2.0 m², with roughly 1.7 m² as the classic reference figure. The result is an estimate from a statistical formula, not a measurement of your actual skin — clinicians use it precisely because it is reproducible, not because it is exact.