Percentage Difference Calculator
Calculate the percentage difference between two values relative to their average — a symmetric comparison with no “original” value.
Your inputs
Results
Percentage difference
40%
- Absolute difference
- 20
- Average of the two
- 50
✓Exact calculation — rounded only for display
What this calculator does
When neither value is the starting point — comparing two measurements or two prices — percentage difference treats both equally.
Formula and method
Difference = |A − B| ÷ ((|A| + |B|) ÷ 2) × 100
Worked example
Calculated by this tool with its default inputs:
Inputs
- Value A: 40
- Value B: 60
Results
- Percentage difference: 40%
- Absolute difference: 20
- Average of the two: 50
How to read the results
Swapping A and B gives the same answer, unlike percentage change.
Assumptions and limitations
- Not appropriate when one value is clearly the baseline; use percentage change instead.
Questions
Why is it 40 % for 40 vs 60?
The difference 20 is divided by the average 50.
Methodology and verification
- Result type
- Exact mathematical calculation (rounded only for display)
- Formula version
- 1.0
- Automated verification
- 3 reference and validation test cases, checked against independently computed values. The site cannot be built if any of them fail.
- Editorial review
- Awaiting human editorial review. The explanation was drafted with AI assistance; the formula and examples are verified by the automated tests above.
Privacy
Everything you enter is calculated in this browser and is not sent to Numerith or anyone else. Inputs are added to a share link only if you choose to include them. Privacy policy