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BSA (Mosteller)
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⚠️ Medical Disclaimer: BSA calculations are for educational reference only. Drug dosing decisions must be made by a licensed healthcare provider. Never adjust chemotherapy or other drug doses without physician oversight.
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Sources & Methodology
BSA formulas per original publications: Du Bois (1916), Mosteller (1987), Haycock (1978), and Gehan-George (1970).
Du Bois D, Du Bois EF — Archives of Internal Medicine (1916)
Original BSA formula: BSA = 0.007184 x W^0.425 x H^0.725. The historical clinical standard.
Mosteller RD — New England Journal of Medicine (1987)
Simplified formula: BSA = sqrt(H x W / 3600). Recommended by ASCO for oncology dosing. nejm.org
Haycock GB et al. — Journal of Pediatrics (1978)
Formula: BSA = 0.024265 x W^0.5378 x H^0.3964. Validated for pediatric populations.
Du Bois: BSA = 0.007184 x W(kg)^0.425 x H(cm)^0.725
Mosteller: BSA = sqrt(H(cm) x W(kg) / 3600)
Haycock: BSA = 0.024265 x W(kg)^0.5378 x H(cm)^0.3964
Gehan-George: BSA = 0.0235 x W(kg)^0.51456 x H(cm)^0.42246
Total Drug Dose (mg) = Drug Dose (mg/m2) x BSA (m2)
Mosteller: BSA = sqrt(H(cm) x W(kg) / 3600)
Haycock: BSA = 0.024265 x W(kg)^0.5378 x H(cm)^0.3964
Gehan-George: BSA = 0.0235 x W(kg)^0.51456 x H(cm)^0.42246
Total Drug Dose (mg) = Drug Dose (mg/m2) x BSA (m2)
Mosteller: BSA = sqrt(Height(cm) x Weight(kg) / 3600)
Example: 70 kg, 170 cm patient.
BSA = sqrt(170 x 70 / 3600) = sqrt(11900/3600) = sqrt(3.306) = 1.82 m²
At 75 mg/m² drug dose: Total = 75 x 1.82 = 136.5 mg
BSA = sqrt(170 x 70 / 3600) = sqrt(11900/3600) = sqrt(3.306) = 1.82 m²
At 75 mg/m² drug dose: Total = 75 x 1.82 = 136.5 mg
Last reviewed: April 2026
How Is Body Surface Area Calculated?
Body Surface Area (BSA) is a measurement of the total surface area of the human body, expressed in square meters (m²). Unlike body weight alone, BSA correlates more accurately with many physiological parameters — including cardiac output, renal function, and drug distribution — making it the preferred basis for dosing many medications, particularly chemotherapy agents.
Four main formulas are in clinical use. Mosteller is the simplest and most widely recommended for oncology. Du Bois is the original 1916 formula still used in cardiology. Haycock is preferred for pediatric patients. Gehan-George offers another validated alternative, particularly at extremes of body size.
BSA Formula Comparison
| Formula | Year | Best Used For | BSA at 70kg/170cm |
|---|---|---|---|
| Mosteller | 1987 | Oncology (ASCO recommended) | 1.82 m² |
| Du Bois | 1916 | Cardiology, historical standard | 1.83 m² |
| Haycock | 1978 | Pediatrics | 1.83 m² |
| Gehan-George | 1970 | Extremes of body size | 1.81 m² |
Normal BSA Values by Population
| Population | Average BSA | Typical Range |
|---|---|---|
| Adult male | 1.9 m² | 1.6 - 2.2 m² |
| Adult female | 1.6 m² | 1.4 - 1.9 m² |
| Reference standard | 1.73 m² | eGFR normalization basis |
| Neonate | 0.25 m² | 0.2 - 0.3 m² |
| Child (10yr) | 1.14 m² | 0.9 - 1.3 m² |
⚠️ Obese Patients: Standard BSA formulas may overestimate BSA in obese patients, leading to excessive chemotherapy doses. Many oncology guidelines cap BSA at 2.0 m² or use adjusted/ideal body weight for patients with BMI above 30. Always follow institution-specific dosing protocols.
Frequently Asked Questions
BSA is the total surface area of the human body in square meters (m²). It is used in medicine for chemotherapy dosing, cardiac output normalization, and drug dose calculations because it correlates better than weight alone with physiological parameters.
BSA = 0.007184 x Weight(kg)^0.425 x Height(cm)^0.725. This 1916 formula is the original clinical standard, still widely used in cardiology for cardiac output indexing.
BSA = sqrt(Height(cm) x Weight(kg) / 3600). Simple, accurate, and recommended by ASCO for oncology drug dosing. Example: 170cm, 70kg: sqrt(170x70/3600) = 1.82 m².
Average adult male: 1.9 m². Average adult female: 1.6 m². The reference standard of 1.73 m² is used to normalize eGFR values.
Total dose (mg) = Drug dose (mg/m²) x BSA (m²). Example: 75 mg/m² x 1.82 m² = 136.5 mg total dose. BSA-based dosing normalizes drug exposure across patients of different sizes.
No single formula is definitively superior. Mosteller is recommended for oncology. Haycock is preferred for children. Du Bois is the cardiology standard. All four formulas give very similar results for average-sized adults.
Cardiac index (CI) = Cardiac Output / BSA. Normal CI = 2.5-4.0 L/min/m². BSA also normalizes stroke volume, left ventricular mass, and echocardiographic measurements.
Convert: height inches x 2.54 = cm; weight lb / 2.205 = kg. Then apply any formula. This calculator accepts imperial and converts automatically.
BSA = 0.024265 x Weight(kg)^0.5378 x Height(cm)^0.3964. Validated specifically for pediatric patients across a wide age range. Preferred for children over Du Bois.
For many cytotoxic chemotherapy agents, BSA-based dosing reduces pharmacokinetic variability compared to weight-based dosing. For many other drugs, fixed dosing or weight-based dosing is equally appropriate. Always follow drug-specific guidelines.
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