Percentage Difference Calculator
Find the percentage difference between two values using the average of both as the reference point.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
Can't find what you need?
Request a ToolHow to Use the Percentage Difference Calculator
Enter two values to find the percentage difference between them. The result updates live as you type, with no need to press a button.
- Enter Value A. This is the first number you want to compare.
- Enter Value B. This is the second number you want to compare.
- Read the result. The percentage difference appears along with the absolute difference and the average of both values. Copy or Share to save the result.
The formula is: |A - B| / ((A + B) / 2) x 100. This approach is symmetric, meaning the result is the same regardless of which value is A and which is B. It uses the average of both values as the reference point.
About Percentage Difference
Percentage difference measures how far apart two values are relative to their average. Unlike percentage change (which has a direction from old to new), percentage difference is symmetric. Swapping A and B gives the same result. This makes it useful when neither value is the "original" or "reference" and you simply want to know how different the two numbers are.
Common uses include comparing test scores, prices from different stores, measurements from different instruments, or any scenario where two values need to be compared without designating one as the baseline.
Frequently Asked Questions
What is the formula for percentage difference?
The formula is |A - B| / ((A + B) / 2) x 100. Take the absolute difference, divide by the average of both values, and multiply by 100 to get a percentage.
When should I use percentage difference vs. percentage change?
Use percentage difference when comparing two values without a clear "before" and "after." Use percentage change when one value is the starting point and the other is the result, such as tracking price changes over time.
Can percentage difference exceed 100%?
Yes. The maximum percentage difference is 200%, which occurs when one value is positive and the other is zero (or when they have opposite signs). For values of the same sign, it can range from 0% to 200%.