Why Body Surface Area Matters for Drug Dosing
Drug doses are often thought of in terms of body weight, but clinically, Body Surface Area (BSA) is frequently the preferred basis. BSA combines height and weight into a single figure that tracks metabolic rate and blood volume more closely than weight alone. For narrow-margin drugs like chemotherapy agents, dosing purely by weight raises the risk of over- or under-dosing, which is why BSA-based calculation became the clinical standard.
The Mosteller Formula and How It Works
This calculator defaults to the widely used Mosteller formula, √(height × weight ÷ 3600), and also shows the Du Bois formula result for comparison. If you know your prescribed mg/m² rate, multiplying it by your BSA gives a reference estimate of the total dose.
Reference Only — Not a Substitute for Prescription
This tool exists purely to provide a formula-based reference figure. Actual dosing decisions depend on kidney and liver function, concurrent medications, and lab results, and must be made by a doctor or pharmacist. Use this result to understand your prescription better, not to adjust your own dosing.
Frequently Asked Questions
BSA reflects metabolic rate and blood volume more closely than weight alone, so it's the standard basis for dosing narrow-margin drugs like chemotherapy agents.
No. This tool provides a formula-based reference figure only. Actual dosing must always follow a doctor's or pharmacist's prescription and judgment.
The tool uses the widely adopted Mosteller formula by default, with the Du Bois formula result shown alongside for comparison.