General and clinical
Body surface area (BSA)
Body surface area estimates the area of a person’s skin from height and weight. It is the basis for chemotherapy dosing, some pediatric dosing, and cardiac index.
Enter the values
Mosteller is the usual choice and the easiest to check by hand.
The result appears as you type.
Nothing is sent anywhere. The calculation runs entirely in your browser.
This calculator is provided for reference and education. It does not replace clinical assessment, examination, current guidelines, local protocol, or professional judgment. Verify every result before acting on it. Nirogix accepts no liability for clinical decisions made using this tool.
The formula
- Mosteller: BSA = √[ height (cm) × weight (kg) ÷ 3600 ]
- Du Bois: BSA = 0.007184 × height (cm)^0.725 × weight (kg)^0.425
- Haycock: BSA = 0.024265 × height (cm)^0.3964 × weight (kg)^0.5378
Worked example
70 kg and 175 cm, Mosteller → √(175 × 70 ÷ 3600) = √3.403 = 1.84 m²
When to use it
- Dosing a drug written per square meter
- Indexing a cardiac output or a filtration rate
And when not to
- The formulas disagree by a few percent. Pick one per patient and stay with it.
- BSA-based chemotherapy dosing in obesity and in the very small is a specialist decision, not an arithmetic one.
References
- Simplified calculation of body-surface area — Mosteller RD, New England Journal of Medicine, 1987
- A formula to estimate the approximate surface area — Du Bois D & Du Bois EF, Archives of Internal Medicine, 1916
Last reviewed 07/09/2026.
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