AI Health Assistant
BetaAsk questions about your calculation results
3 free questions per session
AI provides general information, not medical advice. Always consult a healthcare professional.
About This Calculator
Body surface area is a measurement used in medicine to calculate drug dosages, assess burn severity, and determine cardiac output norms. This calculator applies formulas such as Du Bois or Mosteller using your height and weight to estimate total skin area in square meters. BSA-based dosing is often more accurate than weight-based dosing for medications with narrow therapeutic windows, particularly in oncology.
Quick Tips
- 1 BSA is used for drug dosing — small errors can mean wrong medication amounts.
- 2 The Mosteller formula is simplest and accurate enough for most uses.
- 3 BSA scales more reliably than weight alone for metabolic comparisons.
Example Calculation
A patient weighs 78 kg and is 174 cm tall (Du Bois formula).
BSA: 1.93 m2 | Mosteller: 1.92 m2 | Average adult: 1.7 m2 | Used for drug dosing and burn assessment
What is Body Surface Area?
Body Surface Area (BSA) is the measured or calculated surface area of a human body, expressed in square meters (m²). Average adult BSA is approximately 1.7 m². BSA is used in medicine to calculate drug dosages (especially chemotherapy), determine cardiac output, and assess burn severity.
Du Bois vs Mosteller Formula
The Du Bois formula (1916) is: BSA = 0.007184 × weight(kg)^0.425 × height(cm)^0.725. The Mosteller formula (1987) is simpler: BSA = √(height(cm) × weight(kg) / 3600). Both produce similar results, with the Mosteller formula being preferred in many clinical settings for its simplicity.
Medical Applications of BSA
BSA is primarily used in oncology to calculate chemotherapy dosages, as drug clearance correlates better with BSA than body weight alone. It is also used to calculate glomerular filtration rate (kidney function), cardiac index, and fluid resuscitation formulas for burn patients (Parkland formula).
BSA in Fitness and Sports
In sports science, BSA is used to calculate metabolic rate more accurately, assess thermoregulation capacity (larger surface area means more heat dissipation), and normalize physiological measurements across different body sizes for fair comparison between athletes.
Frequently Asked Questions
The average BSA for adult men is approximately 1.9 m² and for adult women is approximately 1.6 m². BSA ranges from about 1.2 m² for small adults to 2.5 m² or more for very large individuals. Newborns have a BSA of about 0.25 m².
BSA correlates more closely with metabolic rate and organ function than body weight alone. Drug clearance by the liver and kidneys relates better to BSA. This makes BSA-based dosing more accurate, especially for drugs with narrow therapeutic windows like chemotherapy agents.
Multiply your height in inches by 2.54 to get centimeters. For example, 5'10" = 70 inches × 2.54 = 177.8 cm. You can also use the conversion: feet × 30.48 + inches × 2.54.
Both formulas are clinically validated and produce similar results (typically within 0.02 m²). The Du Bois formula is the historical standard, while the Mosteller formula is newer and simpler to calculate. Most clinical guidelines accept either formula.