Relative Percent Difference (RPD) Calculator

Formula

To calculate the Relative Percent Difference (RPD):

\[ \text{RPD} = \frac{|X2 - X1|}{\left(\frac{X2 + X1}{2}\right)} \times 100 \]

Where:

\( \text{RPD} \) is the relative percent difference (%)
\( X2 \) is the final value
\( X1 \) is the initial value

What is RPD?

RPD, short for relative percent difference, is a measure of the change in a value relative to the average of that value. For example, if a value in an experiment changed from 10 to 20, the RPD would be relative to the average of those two numbers. \( \frac{10 + 20}{2} = 15 \).

Example Calculation 1

Let's assume the following values:

Initial Value \( X1 \) = 10
Final Value \( X2 \) = 20

Step 1: Calculate the relative percent difference:

\[ \text{RPD} = \frac{|20 - 10|}{\left(\frac{20 + 10}{2}\right)} \times 100 = \frac{10}{15} \times 100 = 66.67 \% \]

So, the Relative Percent Difference is 66.67%.

Example Calculation 2

Let's assume the following values:

Initial Value \( X1 \) = 30
Final Value \( X2 \) = 45

Step 1: Calculate the relative percent difference:

\[ \text{RPD} = \frac{|45 - 30|}{\left(\frac{45 + 30}{2}\right)} \times 100 = \frac{15}{37.5} \times 100 = 40 \% \]

So, the Relative Percent Difference is 40%.