Percentage Difference Calculator
Find the percentage difference between two values. Useful for comparing prices, test scores, measurements, and statistics.
Free Percentage Difference Calculator
The SmarterSources Percentage Difference Calculator finds the relative difference between two numbers as a percentage of their average. This is useful when neither value is an "original" or "reference" value — you simply want to know how far apart they are.
How to Calculate Percentage Difference
The formula is: Percentage Difference = |Value 1 - Value 2| / ((Value 1 + Value 2) / 2) × 100. The result is always positive because it uses the absolute difference. It represents how different the two values are relative to their average.
Percentage Difference vs. Percentage Change
Percentage difference is symmetric — swapping the values gives the same result. Use it when comparing two independent values (e.g., prices at two stores). Percentage change is directional — it measures how much a value increased or decreased from an original. Use it when you have a before and after.
Frequently Asked Questions
When should I use percentage difference vs. percentage change?
Use percentage difference when comparing two independent values with no "original." Use percentage change when one value came before the other (like year-over-year growth).
Can percentage difference exceed 100%?
Yes. If the two values are very different, the percentage difference can exceed 100%. The maximum is 200% (when one value is 0 and the other is positive).
Is my data safe?
Yes. This calculator runs entirely in your browser. No data is sent to any server and nothing is stored.