What is the Mosteller BSA Calculator?
Body surface area (BSA) is a measure of the total area of the human body, expressed in square meters (m²). It is widely used in medicine — especially for dosing chemotherapy and other drugs, and for indexing physiological measurements like cardiac output. The Mosteller formula, published in 1987, is one of the simplest and most popular BSA equations because it only requires a square root.
How to Use It
Enter your weight in kilograms and your height in centimeters, then read the resulting BSA in square meters. Both inputs must be positive numbers. The result updates based on the values you provide.
The Formula Explained
The Mosteller equation is:
$$\text{BSA} = \sqrt{\dfrac{\text{Weight (kg)} \times \text{Height (cm)}}{3600}}$$
where weight is in kilograms and height is in centimeters. The constant 3600 normalizes the product so the result lands in square meters. Because it relies on a single square root rather than fractional powers, it is easy to compute by hand or calculator.
Worked Example
For an adult weighing 70 kg and standing 175 cm tall: $$\text{BSA} = \sqrt{\frac{70 \times 175}{3600}} = \sqrt{\frac{12250}{3600}} = \sqrt{3.4028} \approx \textbf{1.84 m}^2$$. A more typical "average adult" reference is about \(1.7\) m².
FAQ
Which BSA formula does this use? The Mosteller (1987) formula. Other common formulas include Du Bois and Haycock, which may give slightly different values.
What units are required? Weight in kilograms and height in centimeters. The output is in square meters.
Why is BSA used in medicine? Many drug dosages, particularly chemotherapy, are calculated per square meter of body surface area because BSA correlates better with metabolic mass than body weight alone.
