Body Surface Area Calculator

BSA is used in medicine to calculate drug doses, especially for chemotherapy, where dosing by weight alone is less accurate. It is also used to calculate cardiac index, fluid replacement in burns, and other clinical parameters. Most chemotherapy drugs are dosed in mg/m2.

The Mosteller formula is most commonly used due to its simplicity (BSA = sqrt(Height x Weight / 3600)). Du Bois (1916) was the first widely used formula but is less accurate at extremes. Haycock is preferred in pediatrics. No single formula is perfect for all body types.

Average adult male BSA: ~1.9 m2. Average adult female: ~1.6 m2. These are the reference values used in clinical studies and standard drug dosing charts. Values range from ~0.25 m2 (newborn) to 2.5+ m2 for very large adults.

BMI (Body Mass Index) = weight/height2 — measures weight relative to height, used for general health screening. BSA (Body Surface Area) = estimate of skin area — used for clinical drug dosing. BSA is not affected by adiposity in the same way BMI is and is more relevant for drug metabolism.

Chemotherapy drugs are often highly toxic at wrong doses. Dosing by body surface area (mg/m2) rather than just weight provides a better approximation of drug distribution volume, metabolic rate, and toxicity threshold. However, actual dosing decisions are complex and made by oncologists based on many factors.