Body Surface Area Calculator

Calculate body surface area (BSA) using five widely used clinical formulas, from height and weight.

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Why body surface area matters clinically

BSA correlates more closely with metabolic mass than body weight alone, since it accounts for both height and weight together. It's used to determine drug dosages (especially chemotherapy), calculate cardiac index, and reference burn treatment extent, among other clinical applications.

Why five different formulas

Direct BSA measurement is impractical, so researchers have published several regression formulas derived from different study populations over the decades. Mosteller's formula is simplest and widely used for its ease of calculation; Du Bois is one of the oldest and most historically referenced; the others were developed to improve accuracy for specific populations (like children, for Haycock). They typically agree within a few percent of each other.

This tool is for reference and educational purposes. Actual clinical dosing decisions should always be made by a qualified healthcare provider using validated clinical protocols.

Common questions

Which formula should I use?

Mosteller is the most commonly cited in modern clinical practice for its simplicity, though DuBois remains widely referenced historically. For any medical decision, follow your healthcare provider's preferred formula.

Why do the results differ slightly between formulas?

Each formula was derived from a different set of measured subjects using different regression techniques, so small systematic differences between them are expected and normal.

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