Body Surface Area Calculator
The Body Surface Area (BSA) Calculator estimates the total surface area of the human body using height and weight. BSA is commonly expressed in square meters (mΒ²) and is used in some medical calculations, research, and clinical settings.
What Is Body Surface Area?
Body surface area is an estimate of the external surface area of the body. It differs from body mass, BMI, or body fat percentage because it considers both height and weight to estimate the overall size of the body's surface.
BSA is particularly useful in healthcare because certain measurements and medication calculations may be based on body surface area rather than body weight alone.
How Is Body Surface Area Calculated?
Several formulas can be used to estimate BSA. One of the most widely used is the Mosteller formula:
BSA = β[(Height Γ Weight) Γ· 3600]
In this formula, height is entered in centimeters and weight in kilograms. The resulting BSA is expressed in square meters (mΒ²).
Example of a BSA Calculation
Suppose a person is 170 cm tall and weighs 70 kg. Using the Mosteller formula:
BSA = β[(170 Γ 70) Γ· 3600]
BSA = β3.3056
BSA β 1.82 mΒ²
Therefore, the estimated body surface area for this example is approximately 1.82 square meters.
Why Use a Body Surface Area Calculator?
BSA calculations can be useful in medical and scientific contexts where body size needs to be considered alongside other measurements.
- Estimate body surface area from height and weight.
- Provide a BSA value in square meters.
- Support certain clinical calculations when BSA is appropriate.
- Use BSA as a reference in medical research and healthcare settings.
Common BSA Formulas
The Mosteller formula is popular because it is relatively simple and requires only height and weight. Other formulas, including the Du Bois and Du Bois formula, have also been used to estimate body surface area.
Du Bois and Du Bois formula:
BSA = 0.007184 Γ Height0.725 Γ Weight0.425
Height is measured in centimeters and weight in kilograms. Different formulas may produce slightly different BSA estimates for the same person.
What Is a Normal Body Surface Area?
BSA varies according to body size, so there is no single value that is considered normal for everyone. Adults often have BSA values around 1.5 to 2.0 mΒ², but individual results can be outside this range depending on height and weight.
BSA should therefore be interpreted in relation to the individual rather than compared with one fixed target value.
BSA vs. BMI
BSA and BMI are different measurements. BMI uses height and weight to calculate a weight-to-height index, while BSA estimates the body's external surface area.
For example, BMI is commonly used as a general screening measure related to weight status, whereas BSA may be used in certain clinical calculations where body size is relevant.
Is BSA Used in Medicine?
Yes. Body surface area is used in some medical settings, including certain calculations involving medication dosing, kidney function, cardiac measurements, and other clinical assessments.
However, BSA should not automatically be used to determine a medication dose. The appropriate calculation depends on the specific medication, patient characteristics, and clinical guidelines.
How Accurate Is a BSA Calculator?
A BSA calculator provides an estimate based on a mathematical formula. It does not directly measure the physical surface area of the body.
Different BSA formulas can produce slightly different results. For general calculations, the Mosteller formula is convenient and widely used, but a healthcare professional may use a particular formula depending on the clinical situation.
Important Note
This calculator provides an estimated body surface area for general informational and educational purposes. BSA calculations can have important clinical applications, but the appropriate formula and interpretation may vary depending on the situation. Do not use an online BSA result to make medication or treatment decisions without professional medical guidance.