The Mosteller formula
BSA (m²) = √(height (cm) × weight (kg) ÷ 3600). For 170 cm and 70 kg: √(11,900 ÷ 3600) = √3.31 = 1.82 m². Published as a one-paragraph letter in the New England Journal of Medicine in 1987, it replaced the 1916 Du Bois formula in many hospitals because it can be worked out on a basic calculator.
Why surface area, not weight?
Many body processes, including metabolic rate, heart output and kidney filtration, scale more closely with surface area than with weight. Dosing by BSA was adopted to make doses more consistent between people of different sizes, though for many drugs clinicians now also consider kidney function and other factors.
Questions people ask
What is body surface area used for?
Clinicians use BSA to scale doses of some medicines, especially chemotherapy, and to index measurements such as cardiac output (cardiac index) and kidney function. Your care team will always calculate doses themselves.
What is a normal body surface area?
Many adults fall between about 1.6 and 2.1 m². An often-quoted average is about 1.7 m² for women and 1.9 m² for men, but it depends entirely on height and weight.
Which BSA formula is used most?
The Mosteller formula (1987), √(height cm × weight kg ÷ 3600), is widely used because it’s simple and agrees closely with the older Du Bois formula for typical adults.
Sources
- Mosteller RD (1987). Simplified calculation of body-surface area. N Engl J Med 317:1098.
- Du Bois D, Du Bois EF (1916). A formula to estimate the approximate surface area if height and weight be known. Arch Intern Med 17:863–871.
Every formula on VitalMetrics is listed with its original reference on Sources & methods.