Body surface area (BSA) is a clinical measurement most people never think about — until a medication dose needs to be calculated more precisely than weight alone allows.
Bsa calculator medication dosing, why not just use weight
Certain medications, most notably chemotherapy drugs, are dosed by BSA rather than weight because it correlates better with metabolic rate, blood volume, and organ function across a wide range of body sizes — a heavier and a lighter patient with similar BSA often need doses closer together than weight alone would suggest.
Mosteller formula calculator, the clinical standard
Several BSA formulas exist, but Mosteller is the one most commonly cited in clinical references — a square root of (height × weight ÷ 3,600) that's simple enough to calculate quickly while remaining accurate. For a 180 cm, 80 kg adult, it gives 2.00 m².
Body surface area from height and weight, two inputs only
Unlike more complex historical formulas (like Du Bois), Mosteller needs just height and weight — no additional constants or lookup tables — which is part of why it became the standard for quick clinical calculations.
