Compare two values when neither one is the starting point. The order of the values does not change the result.
Percentage difference = |A − B| ÷ average magnitude × 100.
Percentage difference compares the gap between two values with their average rather than treating either value as the original. For ordinary positive values, use |A − B| ÷ ((A + B) ÷ 2) × 100.
Use percentage difference when the two values are peers, such as two measurements or two quoted prices. Use percentage change when one value is clearly the starting value and direction matters.
No. Percentage difference is symmetric, so swapping the values produces the same result.
Yes. Values that are very far apart can produce a percentage difference greater than 100%.
The percentage difference is undefined because the average baseline is zero.