Percentage Difference Calculator
Compare two values without choosing a baseline. Percentage difference uses the average of the two numbers, making the result symmetric.
Privacy: calculations run locally in your browser. No inputs are stored or transmitted.
How it works
Formula (symmetric):
Percentage difference = ( |A − B| ÷ ((|A| + |B|) ÷ 2) ) × 100
- Absolute difference: |A − B|
- Average magnitude: (|A| + |B|) / 2
- Symmetric: swapping A and B gives the same result
Examples
- A 120, B 90 → |diff| 30, average 105 → 28.57%
- A 50, B 60 → |diff| 10, average 55 → 18.18%
- A 0, B 80 → |diff| 80, average 40 → 200%
FAQ
- What is percentage difference?
Percentage difference compares two values without choosing a starting value. It uses the average of the two values as the denominator.
- How is it different from percentage change?
Percentage change uses a baseline (“from” value) and divides by that baseline. Percentage difference divides by the average of the two values instead.
- Can the result be over 100%?
Yes. If the two values are very far apart relative to their average, the percentage difference can exceed 100%.
- What if one or both values are 0?
If both values are 0, the average is 0 and the percentage difference is undefined. If only one is 0, it can still be computed because the average is non-zero.
- Is this the same as “percent error”?
No. Percent error typically compares a measured value to a reference/true value. Percentage difference treats both values symmetrically.