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BSA Calculator — Haycock Formula
The Haycock formula for body surface area is BSA (m²) = 0.024265 × weight in kg^0.5378 × height in cm^0.3964, and it is one of the equations commonly favoured in infants and children because it was validated across a wide range of body sizes including neonates. This calculator applies Haycock and shows it beside Mosteller, Du Bois, Gehan-George and Boyd, so you can see how closely they track at average size and where they separate at the extremes. For a person 180 cm tall weighing 75 kg, Haycock gives approximately 1.94 m². Enter height and weight in metric or imperial units to compare all five formulas at once. BSA (m²) is used for chemotherapy and drug dosing, cardiac index and pediatric calculations, where getting the formula right matters most. This is an estimate — clinical and chemotherapy dosing must be independently clinically verified. Free, private, and computed entirely in your browser.
Haycock: BSA (m²) = 0.024265 × kg^0.5378 × cm^0.3964
- Worked example: 180 cm / 75 kg ≈ 1.94 m²
- Compared side by side with Mosteller, Du Bois, Gehan-George and Boyd
Frequently asked questions
What is the Haycock BSA formula?
Haycock BSA (m²) = 0.024265 × weight in kg^0.5378 × height in cm^0.3964. It was validated across a wide size range including neonates, which is why it is often used in pediatrics. For 180 cm and 75 kg it gives ≈ 1.94 m². It is an estimate — verify clinically for dosing.
Which BSA formula is best for children?
Haycock and Mosteller are generally favoured in infants and children, because Haycock was derived from a size range that included very small patients and Mosteller tracks it closely. Du Bois, derived from only nine adults, is less suited to the extremes. When a pediatric dose depends on BSA, use the formula your clinical protocol specifies.