Body Surface Area Calculator

What is Body Surface Area (BSA)?

Body Surface Area (BSA) is the measured or calculated surface area of a human body. For many clinical purposes, BSA is a better indicator of metabolic mass than body weight because it is less affected by abnormal adipose mass.

Common uses include:

• Chemotherapy Dosing: Many cancer drugs have a narrow therapeutic index, so dosage is calculated per square meter of body surface (mg/m²) to minimize toxicity while ensuring effectiveness.
• Cardiac Index: This hemodynamic parameter relates cardiac output (from the heart) to body size, providing a better assessment of heart function than cardiac output alone.
• Burn Assessment: While the "Rule of Nines" is used for quick estimates, BSA provides a baseline for total area.
• Renal Function: Glomerular filtration rate (GFR) is often normalized to a standard BSA of 1.73 m².

Formulas Used

Several formulas have been developed over the years to estimate BSA. This calculator provides results for the most common ones:

• Mosteller (1987): The most practical formula. It is easy to remember and calculation involves a square root.
  BSA = √ [ (Height(cm) x Weight(kg) ) / 3600 ]
• Du Bois & Du Bois (1916): The classic standard for decades.
  BSA = 0.007184 x Weight(kg)^0.425 x Height(cm)^0.725
• Haycock (1978): Often used for children and infants.
• Gehan & George (1970): Another robust statistical variation.

For standard weight assessments, you might also find our BMI Calculator or Healthy Weight Calculator useful.