Percentage Difference Calculator
Work out the percentage difference between two numbers, useful for comparing prices, scores or measurements quickly.
Your results
Calculation breakdown
- Percentage difference
- |A − B| ÷ ((|A| + |B|) ÷ 2) × 100
Worked example
Comparing two quotes of $80 and $100, the percentage difference is |80 − 100| ÷ 90 × 100 = 22.2%, treating neither figure as the baseline.
Assumptions
- Percentage difference treats both values symmetrically, unlike percentage change which has a fixed baseline.
- The result is always shown as a positive percentage.
How this calculator works
This calculator finds the percentage difference between two values, treating them symmetrically rather than as an original-versus-new comparison. It divides the absolute difference by the average of the two numbers and expresses the result as a percentage, which is handy when neither value is clearly the baseline.
Frequently asked questions
How is percentage difference different from percentage change?
Percentage change uses one value as a fixed baseline, while percentage difference treats both values equally by dividing by their average — useful when there's no obvious 'before' figure.
Can the result be negative?
No, this calculator reports the absolute percentage difference, so the result is always zero or positive.
What if both numbers are zero?
The calculation is undefined when both values are zero, so the calculator shows an error message instead of a result.
Editorial review and responsibility
Reviewed by the CalcAussie editorial team on 21 September 2026. Review scope: Method, Australian terminology, material assumptions, source links and user-facing limitations.
Calculator results remain estimates based on the figures entered. Check material decisions against current official information and report a suspected error so it can be reproduced and corrected.