Body Surface Area Calculator
Use our free medical calculator to determine your body surface area (BSA). The calculator uses the most common formulas, including Du Bois, Mosteller, and Haycock formulas.
Your Body Surface Area
What is Body Surface Area (BSA)?
The Body Surface Area (BSA) is the total surface area of a human body. In medical systems, body surface area is used to define a variety of calculations, including:
- Drug dosage: Doses of many medical drugs, especially chemotherapy drugs, are often defined relative to BSA
- Burns: Doctors use body surface area to calculate the percentage of burned skin
- Cardiac index: Cardiac index calculation requires a person's BSA
- Glomerular filtration rate: Renal function is sometimes calculated using a person's BSA
BSA accounts for many physiological variables, making it a more accurate metric than weight for calculating drugs dosages.
How to Use the Body Surface Area Calculator
Our body surface area calculator is straightforward to use:
- Choose the formula: Mosteller is a common calculation, but you may also choose Du Bois and Haycock formulas
- Input your height: Enter your height into the calculator in inches or cm. For example, for 5'10", enter 70.
- Input your weight: You should input your weight in pounds or kg.
- Click "Calculate Body Surface Area": The calculator will show your BSA in square meters (m²).
BSA Formulas Explained
There are several formulas for calculating BSA. Here are the most common three formulas:
1. Mosteller Formula
BSA (m²) = √[(Height in cm × Weight in kg) / 3600]
The Mosteller formula is common in medical systems, as it is easy to remember and produces accurate results for adults and children.
2. Du Bois Formula
BSA (m²) = 0.007184 × Height(cm)^0.725 × Weight(kg)^0.425
The Du Bois formula was created in 1916 and is still one of the most accurate ways of calculating body surface area.
3. Haycock Formula
BSA (m²) = 0.024265 × Height(cm)^0.3964 × Weight(kg)^0.5378
The Haycock formula is often used for pediatric patients. The formula produces accurate results across a variety of ages and weights.
Normal BSA Values
Body surface area depends on age, gender, and general body size. The table below shows the average body surface area for different populations:
| Population | Average BSA (m²) |
|---|---|
| Infant (0-1 year) | 0.2 - 0.5 |
| Child (1-5 years) | 0.5 - 0.8 |
| Child (5-12 years) | 0.8 - 1.2 |
| Adult Women | 1.5 - 1.8 |
| Adult Men | 1.7 - 2.0 |
Clinical Uses of BSA
BSA calculations have a variety of uses within the medical field, including:
- Chemotherapy drug dosage: The BSA is used to calculate the doses of many chemotherapy drugs. It helps to make sure a patient gets the right dose without overdose toxicity.
- Burns: Doctors use something called the Rule of Nines, which is based on the BSA.
- Cardiac index: Cardiac index (CI) is calculated by dividing a person's cardiac output by their BSA.
- GFR: A person's Glomerular filtration rate (GFR) is sometime calculated using a person's BSA.
- Nutritional Status: BSA is sometimes used in nutritional status calculations to help estimate a person's caloric needs.
BSA vs BMI
BSA and BMI are two similar but distinct metrics. Both measurements can predict a person's health risks, but they are different calculations. While BMI is a measurement of body fat, BSA is a surface area measurement. As such, BMI is useful for assessing a person's weight status, while BSA is a better predictor of health risks such as heart disease.
While BMI is better for tracking a person's weight status, body surface area is more useful in medical settings. For a more complete look at your body, try our Army Body Fat Calculator and FFMI Calculator.
FAQs About Body Surface Area Calculator
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