Body surface area (BSA) in m² from height and weight by the Mosteller, DuBois and Haycock formulas, with the spread between them.
Your body surface area is about 1.84 m² by Mosteller; DuBois gives 1.85 m² and Haycock 1.85 m², a spread of 0.2 %.
Body surface area (BSA) is the total area of the skin, estimated here from height and weight with three formulas. Mosteller (1987) takes the square root of height in centimetres times weight in kilograms divided by 3600. DuBois (1916) and Haycock (1978) raise weight and height to fitted powers. The spread shows how far the three disagree.
Many chemotherapy drugs are dosed in mg per m², cardiac output is divided by BSA to give cardiac index, and kidney function (eGFR) is reported per 1.73 m². At the default 70 kg and 175 cm, Mosteller gives 1.84 m², and DuBois and Haycock both round to 1.85 m².
For adults of average build the formulas agree within about 1.5 %, but they drift apart in obesity: at 120 kg and 170 cm they range from 2.28 to 2.44 m². Dosing protocols state which formula their doses assume.
Checked against: Python 3.8 math: √(175 × 70 / 3600) = 1.844662; 0.007184 × 70^0.425 × 175^0.725 = 1.848143; 0.024265 × 70^0.5378 × 175^0.3964 = 1.846776
Checked against: Python 3.8 math with 90.718474 kg and 182.88 cm: 2.146741, 2.130382, 2.160487
Checked against: Python 3.8 math: 0.456435, 0.437306, 0.463505
Checked against: Python 3.8 math: 0.220479, 0.208616, 0.224415
About 1.8 m². In 3,613 UK adults receiving chemotherapy in 2005, Sacco and colleagues (PLoS One 2010) found a mean of 1.79 m²: 1.91 m² for men and 1.71 m² for women. eGFR is normalised to a reference adult of 1.73 m², so a person with a BSA of 2.1 m² has an absolute kidney filtration rate about 21 % higher than the reported eGFR.
BSA in m² equals the square root of height in centimetres times weight in kilograms, divided by 3600. For 175 cm and 70 kg that is √(175 × 70 ÷ 3600) = √3.40 = 1.84 m². R. D. Mosteller published it in a 1987 letter to the New England Journal of Medicine as a simpler alternative to the DuBois formula that can be worked out on a pocket calculator.
DuBois is the least suited to small children. Haycock and colleagues measured 81 subjects from premature infants to adults and found that the DuBois formula increasingly underestimated surface area below 0.7 m², by 7.96 % in newborns. For a 3.5 kg, 50 cm newborn, DuBois gives 0.209 m² against Haycock's 0.224 m² and Mosteller's 0.220 m². DuBois itself was fitted to only 9 people.
Metabolic rate, blood volume and drug clearance were found to scale more closely with surface area than with weight across body sizes, so mg per m² became the standard way to scale cytotoxic doses. A 75 mg/m² dose for a 1.84 m² adult is 138 mg. BSA explains only part of the variation in clearance between patients, and some drugs, such as carboplatin, are dosed on kidney function instead.
Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 4 worked examples whose answers come from independent sources; for example, “70 kg, 175 cm” is checked against Python 3.8 math: √(175 × 70 / 3600) = 1.844662; 0.007184 × 70^0.425 × 175^0.725 = 1.848143; 0.024265 × 70^0.5378 × 175^0.3964 = 1.846776.
Mosteller RD. Simplified calculation of body-surface area. N Engl J Med 1987;317(17):1098; DuBois D, DuBois EF. A formula to estimate the approximate surface area if height and weight be known. Arch Intern Med 1916;17:863–871; Haycock GB, Schwartz GJ, Wisotsky DH. Geometric method for measuring body surface area: a height-weight formula validated in infants, children, and adults. J Pediatr 1978;93(1):62–66.
For information only, not medical advice. These formulas describe populations, not you; talk to a clinician before acting on a result.
4 worked examples with independently sourced answers ship with this calculator. They run in the test suite; you can run them here too.
Dose by weight from a mg/kg rate and body weight, capped at the single and daily maximum, with the liquid volume in mL for a given strength.
Body mass index (BMI) from height and weight in metric or imperial units, with the WHO adult category and the healthy weight range for your height.
Lean body mass (LBM) from height, weight and sex by the Boer, James and Hume formulas, with the implied body fat percentage.
Body fat percentage by the US Navy tape method, Jackson-Pollock 3- or 7-site skinfolds, or from BMI, with fat and lean mass and the ACE category.
Ideal body weight (IBW) for your height and sex by the Devine, Robinson, Miller and Hamwi formulas, with the healthy BMI weight range.
Waist-to-hip ratio and waist-to-height ratio from tape measurements, with the WHO risk cut-offs, the NICE bands and the WHO waist size category.
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