Why Pediatric BSA Needs a Different Calculation
Children have proportionally larger heads and torsos relative to total body size than adults, and these proportions keep shifting throughout growth. Applying an adult BSA formula directly can introduce meaningful error, which is why clinicians generally use the Haycock formula, known to be more accurate for pediatric patients. This calculator defaults to Haycock and also shows the Mosteller result for comparison.
How the Calculation Works
The Haycock formula is 0.024265 × height^0.3964 × weight^0.5378. If you know the prescribed mg/m² rate, multiplying it by this BSA value gives a reference estimate of total dose. BSA-based dosing is considered more precise than weight-based dosing alone for children, which is why it's the standard for drugs requiring careful dose control, such as chemotherapy agents.
Reference Only — Always Follow a Specialist's Prescription
This calculator provides only a formula-based reference figure. Actual pediatric dosing decisions must weigh age, kidney/liver function, concurrent medications, and the child's condition, and must be made by a pediatrician and pharmacist. Newborns and infants undergo especially rapid physical changes that further limit BSA calculation accuracy, so never use this result to adjust dosing yourself — always confirm through professional pediatric care.
Frequently Asked Questions
Children's body proportions differ from adults', so the Haycock formula, known to be more accurate for pediatric patients, is generally used. The Mosteller result is also shown for comparison.
Absolutely not. Pediatric drug dosing must be finely tuned based on age, weight, kidney/liver function, and the child's condition, and must always follow a pediatrician's or pharmacist's prescription.
Newborns and infants undergo rapid physical changes, which makes BSA-based estimates even less reliable for this age group. Dosing decisions for infants must always go through a pediatric specialist.