Body Surface Area Calculator (BSA)
Body surface area (BSA) is used in medicine to scale medication doses — most notably in chemotherapy — and to index physiological measurements such as cardiac output, because it tracks metabolic mass better than weight alone. This tool computes BSA with the Mosteller formula (√(height × weight ⁄ 3600)), the most common in clinical practice, and the classic Du Bois formula for comparison. An average adult BSA is about 1.7 m². Dose calculations must always be performed by healthcare professionals; this tool is for information only and is not medical advice.
Frequently asked questions
What is body surface area used for?
Mainly for dosing medications whose effect scales with body size — chemotherapy agents above all — and for indexing measurements such as cardiac output or glomerular filtration rate to body size.
Which BSA formula do hospitals use?
The Mosteller formula is the most widely used because it is simple enough to compute mentally and agrees closely with older formulas. Du Bois (1916) is the historical standard and is still cited in physiology references.
What is a normal BSA value?
Around 1.9 m² for an average adult man and 1.6 m² for an average adult woman; 1.7 m² is often quoted as the adult average. Children's values are substantially lower and are always assessed by clinicians.