Body Surface Area Calculator (Mosteller)
Compute body surface area (BSA) in square meters using the Mosteller formula — the fastest of the widely-accepted BSA equations and the standard for chemotherapy dosing, pediatric mg/m^2 dosing, cardiac index, and GFR normalization. Enter height and weight in your preferred units (cm/in, kg/lb); the tool returns BSA to two decimal places and flags results above 2.2 m^2 where many oncology protocols apply a dose cap.
Enter values and press Calculate to see the result.
Formula
BSA (m^2) = sqrt( height (cm) x weight (kg) / 3600 )
Clinical notes
- Mosteller performs comparably to DuBois & DuBois and Haycock in the general adult population and is trivially fast at the bedside.
- Many oncology regimens cap BSA at 2.0-2.2 m^2 to avoid toxicity in high-BSA patients. Always confirm the protocol's capping rule.
- In infants and neonates, verify the reference used by your institution — some pediatric practices prefer Haycock or Boyd for very low body weights.
- Educational reference only. Not a substitute for a formulary or your institution's dosing protocol.
Source: Mosteller RD. Simplified calculation of body-surface area. N Engl J Med. 1987;317(17):1098.
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