The body surface area calculator uses the Mosteller formula — the most widely adopted BSA formula in clinical practice — to compute BSA in square metres from a patient's height and weight. BSA is used when body weight alone is an insufficient basis for drug dosing, particularly in chemotherapy (where dose is expressed as mg/m²), certain paediatric medications, and burn resuscitation assessment. The normal adult BSA range is 1.6–1.9 m².
| Population | Average BSA |
|---|---|
| Newborn | 0.25 m² |
| Child (2 years) | 0.5 m² |
| Child (10 years) | 1.14 m² |
| Adult female | 1.6 m² |
| Adult male | 1.9 m² |
The Mosteller formula (√[height × weight ÷ 3600]) is the most widely used in clinical practice due to its simplicity and accuracy. Other formulas exist (DuBois, Haycock, Gehan-George) but the differences are clinically insignificant in most contexts. The Mosteller formula is recommended by most oncology guidelines.
The average BSA for an adult female is approximately 1.6 m² and for an adult male approximately 1.9 m². Paediatric BSA ranges from 0.25 m² in newborns to approximately 1.4 m² in a 10-year-old child.