Values for body surface area (BSA) are commonly used in medicine, particularly to calculate doses of chemotherapeutic agents and index cardiac output. Various BSA formulas have been developed over the years. The DuBois and DuBois (Arch Intern Med 1916;17:863-71) BSA equation is the most widely used, although derived from only 9 subjects. More recently, Mosteller (N Engl J Med 1987;317:1098) produced a simple formula, [weight (kg) x height (cm)/3600](1/2), which could be easily remembered and evaluated on a pocket calculator, but validation data in adults are rare. The purpose of the present study was to examine the BSA based on Mosteller's formula in normal-weight (body mass index [BMI], 20-24.9 kg/m(2)), overweight (BMI, 25-29.9 kg/m(2)), and obese (BMI, >/=30 kg/m(2)) adults (>18 years old) in comparison with other empirically derived formulas (DuBois and DuBois, Boyd [The growth of the surface area of the human body. Minneapolis: University of Minnesota Press; 1935], Gehan and George [Cancer Chemother Rep 1970;54:225-35], US Environmental Protection Agency [Development of statistical distributions or ranges of standard factors used in exposure assessments Washington, EPA/600/8-85-010. Office of Health and Environmental Assessment; 1985), Haycock et al [J Pediatr 1978;93:62-6], Mattar [Crit Care Med 1989;17:846-7], Livingston and Scott [Am J Physiol Endocrinol Metab 2001;281:E586-91]) and with the new 3-dimensional-derived formula of Yu et al (Appl Ergon. 2003;34:273-8). One thousand eight hundred sixty-eight patients were evaluated (397 normal weight [BMI, 23 +/- 1 kg/m(2); age, 50 +/- 14 years; M/F, 289/108], 714 overweight [BMI, 27 +/- 1 kg/m(2); age, 52 +/- 11 years; M/F, 594/120], and 757 obese [BMI, 36 +/- 6 kg/m(2); age, 53 +/- 11 years; M/F, 543/215]). The overall BSA was 2.04 +/- 0.24 m(2): 1.81 +/- 0.19 m(2) in normal-weight, 1.99 +/- 0.16 m(2) in overweight, and 2.21 +/- 0.22 m(2) in obese subjects. These values were significantly higher in overweight and obese patients compared with the values using the DuBois-DuBois formula (overall, 2.00 +/- 0.22 m(2), P < .01; normal weight, 1.81 +/- 0.19 m(2), P = .93; overweight, 1.97 +/- 0.16 m(2), P < .01; obese, 2.14 +/- 0.21 m(2), P < .001). We could show an excellent correlation between the results obtained from each formula, with all correlations of 0.97 or higher (between 0.971 and 0.999). Body surface area prediction with the commonly used DuBois formula underestimated BSA in obese patients by as much as 3% (male) to 5% (female). Based on the formula of Yu et al, however, BSA is overestimated when these traditional formulas are used. Although Mosteller's formula is recommended based on its simplicity and suitability for laboratory and clinical work in adults, accuracy studies in whites with 3-dimensional one-pass whole-body scanning are needed.