Body Surface Area Calculator

BSA is the total outer surface of your body, measured in square meters (m^2). Clinicians use it primarily for chemotherapy dosing because drug regimens written in mg/m^2 track metabolic capacity more reliably than weight alone. The calculator shows all four formula results side by side, each rounded to three decimal places.

Use whichever formula your institution's protocol specifies. Mosteller (1987) is the most widely used in adult oncology, and it is easy to verify: sqrt(height_cm x weight_kg / 3600). DuBois and DuBois (1916) is the original reference. Haycock (1978) is validated for infants and children. Gehan-George (1970) appears in some research contexts.

Most adults fall between 1.6 and 2.0 m^2. The traditional pharmacology reference value is 1.73 m^2, the same figure used to normalize kidney function as mL/min/1.73 m^2. Results outside that range are normal for people at the extremes of height or weight, and the calculator flags whether your result falls inside or outside that band.

Each formula was derived from a different patient population using different statistical methods and body-measurement assumptions. For a 70 kg, 175 cm adult all four agree within about 1%. Differences grow at the extremes, such as very small children or very large adults, which is why oncology and pediatric protocols specify a single formula rather than leaving the choice open.

No. It is a math tool only. Chemotherapy dosing also depends on the drug's specific protocol, capped or banded dose limits, organ function, performance status, and pharmacist verification. Always reconcile the calculated BSA against your local protocol before any clinical use.