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Calculates Body Surface Area (Mosteller formula).
Clinical decision-support tool for qualified healthcare professionals. Results are not a diagnosis and should not replace professional clinical judgment.
Body surface area (BSA) is an estimate of the external surface area of the body derived from height and weight. This calculator uses the Mosteller formula, BSA (m²) = √(height × weight / 3600), with height in centimeters and weight in kilograms. It is a widely used way to express physiologic measures that scale with body size. BSA is used clinically to index physiologic parameters such as cardiac output or glomerular filtration rate (for example, eGFR expressed per 1.73 m²) and to scale certain drug doses, most notably in oncology, where chemotherapy is often dosed per square meter. Because it is a derived estimate, its accuracy depends on the quality of the height and weight measurements. BSA reflects body size but not body composition; it does not distinguish lean mass from fat mass, and it becomes less informative at the extremes of weight where body proportions are unusual. It is not drug-specific guidance on its own, and dosing decisions should always follow the relevant medication monograph or protocol rather than the BSA value alone.
Specialty
General MedicineCategory
AnthropometryDifficulty
Basic
Estimated Time
30 seconds
Version
1.0
Last Updated
2026-08-06
Formula
Keywords
Normal Range
Typical adult: 1.4–2.2 m²
Estimates body surface area using the Mosteller formula, used to normalize physiological parameters and to dose selected medications.
Body surface area is calculated with the Mosteller formula: BSA (m^2) = sqrt((height (cm) x weight (kg)) / 3600).
Body weight in kilograms, multiplied by height in the numerator.
Height in centimeters, multiplied by weight before dividing by 3600.
Typical adult BSA ranges from approximately 1.4–2.2 m². The value is used to index physiological parameters such as cardiac output and to dose certain medications normalized to body surface area.
BSA is a standard index in physiology and pharmacology, used to scale physiological variables and guide dosing of several high-risk medications.
A 40-year-old woman weighs 70 kg and is 170 cm tall.
Inputs:
Expected Result: BSA = √((170 × 70) / 3600) ≈ 1.82 m², within the typical adult range.
BSA is used to index physiological parameters (e.g., cardiac output) and to dose certain medications that are normalized to body surface area, particularly in oncology.
The Mosteller formula is most commonly used. Different formulas (DuBois, Haycock) give slightly different results. Use the same formula consistently within your institution.
No. BSA measures total body surface area in m2. BMI measures weight relative to height squared. BSA is used for dosing and physiological indexing; BMI is a screening tool for body fatness.
Disclaimer: This calculator is intended for educational and clinical decision support purposes only. Dosing decisions must always follow drug-specific labeling and institutional protocols.