Percent Difference Calculator
Calculate the symmetric percentage difference between two values and their absolute difference.
Use the same unit for both values. Neither value is treated as the accepted reference.
Data handling
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- Retention
- The tool's working state is kept only while this page is open. Inputs and results are not saved to persistent storage by Got A Tool.
- Export
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How it works
Percent Difference Calculator: a practical guide
A percent difference calculator compares two values symmetrically when neither one is the accepted reference. It expresses their absolute difference as a percentage of their average magnitude.
- STEP 01
Enter the first value and second value using the same unit.
- STEP 02
Use this calculator only when neither value should be treated as the accepted reference.
- STEP 03
Calculate to review the percent difference, absolute difference, and average magnitude.
What this tool does and its limits
Percent difference is the absolute difference between two values divided by their average magnitude, multiplied by 100. It is symmetric: swapping the first and second values does not change the result. Both values cannot be zero because their average magnitude would be zero. This tool does not choose a reference value, assess accuracy, calculate uncertainty, or decide whether a difference is meaningful for a particular field.
Inputs, selected files, and results stay in your browser. The tool does not upload them to Got A Tool or save them to persistent storage.
Questions
Percent Difference Calculator details
When should I use percent difference?
Use it to compare two values when neither is the accepted reference. If one value is a known accepted result, use Percent Error Calculator instead.
Is it the same as percentage change?
No. Percentage change uses a stated starting value as its base. Percent difference treats both values symmetrically.
Why does swapping the values not change the result?
The formula uses an absolute difference and the average magnitude of both values, so the calculation has no direction.
Can both values be zero?
No. The average magnitude would be zero, so the percentage would be undefined.
Keep working
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