Body Surface Area (BSA) Calculator
Accurate Clinical Measurement using Mosteller and Du Bois Formulas
Calculation Results:
*Results are expressed in square meters (m²).
What is Body Surface Area (BSA)?
Body Surface Area (BSA) is a calculated measurement of the total surface area of a human body. Unlike Body Mass Index (BMI), which only accounts for height and weight in a linear fashion, BSA provides a more accurate reflection of metabolic mass. In clinical medicine, BSA is the primary metric used for determining dosages for chemotherapy, corticosteroids, and other high-potency drugs.
Why use a BSA Calculator?
Calculating BSA manually can be prone to errors. Medical professionals utilize these formulas because physiological processes, such as glomerular filtration rate (GFR) and cardiac output, correlate better with BSA than with simple body weight. This calculator provides results based on the two most widely accepted mathematical models:
- Mosteller Formula: Published in 1987, this is the most common formula used due to its simplicity. It is calculated as the square root of (Height in cm multiplied by Weight in kg, divided by 3600).
- Du Bois Formula: One of the oldest and most tested formulas, it uses a constant of 0.007184 and applies specific exponents to height and weight.
BSA Calculation Examples
Consider the following practical applications of these formulas:
| Subject Profile | Height/Weight | Est. BSA (m²) |
|---|---|---|
| Average Male | 178 cm / 80 kg | 1.99 m² |
| Average Female | 163 cm / 65 kg | 1.72 m² |
| Small Adult | 155 cm / 50 kg | 1.47 m² |
Clinical Significance
The average adult BSA is generally considered to be 1.73 m². This specific value is used to normalize various medical measurements, such as kidney function tests. If a patient's BSA is significantly higher or lower than 1.73 m², medications must be adjusted to prevent toxicity or under-dosing. Always consult a healthcare professional for clinical decision-making.