Percent Difference Calculator
Percent difference calculator: compare two numbers against their average to see how far apart they are as a percentage, with the formula.
Editorial review: Farrow (pseudonym; identity and professional credentials are not disclosed). This page is for educational purposes, not professional advice.
Your inputs
Results update as you type. Nothing you enter leaves your device.
Results
- Absolute difference
- 30
- Average
- 65
Example with the starting values
These results use the calculator's initial inputs. Change the values above to calculate your own estimate.
Inputs
- First value
- 50
- Second value
- 80
Results
- Percent difference
- 46.15%
- Absolute difference
- 30
- Average
- 65
How does the Percent Difference Calculator work?
Percent difference = |a − b| / ((a + b) / 2) × 100. It divides by the average of the two numbers, so neither value is treated as the starting point. For 50 and 80: 30 / 65 × 100 = 46.15%.
Because it is symmetric, swapping the two numbers gives the same answer. For a before-and-after change use the percent change calculator instead.
Frequently asked questions
What is percent difference between 50 and 80?
30 divided by the average 65 is 0.4615, or 46.15%. The order of the two numbers does not matter.
Percent difference or percent change?
Percent change divides by the starting value and shows direction. Percent difference divides by the average and treats both numbers equally.
Why is my answer different from a percent increase?
A percent increase divides by the original number. 50 to 80 is a 60% increase but a 46.15% difference.
When should I use percent difference?
Use it to compare two values with no clear baseline, like two measurements or prices from two stores. It treats both numbers equally.