Body Surface Area (BSA) Calculator

About Body Surface Area (BSA) Calculator

Calculate body surface area using the Du Bois formula. This calculator provides instant results with step-by-step explanations to help you understand the calculation process.

How to use this calculator

1. Enter the person's weight in kilograms.
2. Enter the person's height in centimeters.
3. Use the calculator to apply the Du Bois formula and get the BSA result.

The formula explained

• \(\text{BSA}\) = body surface area
• \(\text{weight}\) = body weight in kilograms
• \(\text{height}\) = body height in centimeters
• \(0.007184\) = Du Bois constant
• \(0.425\) = weight exponent
• \(0.725\) = height exponent

Step by step method

1. Take the weight value in kilograms and the height value in centimeters.
2. Raise the weight to the 0.425 power and the height to the 0.725 power.
3. Multiply those two results together, then multiply by 0.007184.
4. Read the final body surface area in square meters.

Worked example

For a person who weighs 70 kilograms and is 175 centimeters tall, here is how the body surface area is found.

1. Substitute the values into the formula: \(\text{BSA} = 0.007184 \times 70^{0.425} \times 175^{0.725}\).
2. Compute the powered terms: \(70^{0.425} \approx 6.022\) and \(175^{0.725} \approx 45.252\).
3. Multiply everything: \(0.007184 \times 6.022 \times 45.252 \approx 1.96\).

Tips and common mistakes

• Use kilograms for weight and centimeters for height, since the formula expects those units.
• Do not mix in pounds or inches unless the tool specifically converts them first.
• Remember that the result is an estimate, not a direct physical measurement.
• If you are checking a calculation, make sure the exponents are applied before multiplying by the constant.

Frequently asked questions