Understanding the Body Surface Area (BSA) Calculator

The Body Surface Area (BSA) calculator determines the total surface area of the human body in square meters (m²). While less common in casual health discussions than BMI, BSA is a vital measurement in clinical settings. It serves as a more reliable indicator of metabolic mass than body weight alone, making it essential for calculating precise dosages of certain medications to ensure patient safety and treatment efficacy.

How to Use This BSA Calculator

Our tool simplifies the calculation of your Body Surface Area. Follow these three easy steps:

  1. Select Units: Choose between U.S. (feet, inches, pounds) or Metric (cm, kg) systems with the toggle at the top.
  2. Enter Your Data: Input your current height and weight into the fields provided.
  3. Calculate: Click the button to view your BSA. The result from the widely-used Mosteller formula is shown first, followed by results from other key formulas for comparison.

Clinical Importance of Body Surface Area

BSA is a cornerstone of personalized medicine, especially in the following areas:

  • Chemotherapy Dosing: BSA is the gold standard for calculating doses of most cytotoxic chemotherapy agents. This practice helps maximize the drug's cancer-fighting ability while minimizing its toxic side effects.
  • Pediatric Medicine: It is frequently used for calculating fluid requirements and drug dosages in children, whose metabolic rates correlate better with BSA than with weight.
  • Pharmacology: Many other drugs, including glucocorticoids and certain antibiotics, are dosed based on BSA to achieve optimal therapeutic levels.
  • Nephrology and Cardiology: Key indicators like the glomerular filtration rate (GFR) and cardiac index are often normalized to BSA to allow for meaningful comparisons between individuals of different sizes.

Common BSA Formulas Explained

This calculator uses several recognized formulas to provide a comprehensive view of your BSA:

  • Mosteller Formula: Published in 1987, it's favored for its simplicity and clinical accuracy: $BSA (m^2) = \sqrt{\frac{Height(cm) \times Weight(kg)}{3600}}$
  • Du Bois Formula: A historical and still widely used formula from 1916: $BSA (m^2) = 0.007184 \times Height(cm)^{0.725} \times Weight(kg)^{0.425}$
  • Haycock Formula: Developed in 1978, it is particularly useful in pediatric and neonatal populations.
  • Gehan & George Formula: Another formula often used in oncology studies, dating back to 1970.

For a complete health overview, consider using this tool alongside our BMI Calculator and Healthy Weight Calculator to better understand your body metrics.