Percent Difference Calculator

Compare two values when neither one is the starting point, such as two measurements or two prices.

Fractions and decimals both work.
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Percent Difference
Absolute difference
Average
For comparison: percent change A → B
Work

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How to Calculate Percent Difference

Percent difference treats both values equally: it divides the gap by their average, so swapping A and B gives the same answer.

Percent difference = |A − B| ÷ ((A + B) ÷ 2) × 100

Worked Example

Tips

Use percent change when one value is clearly the "before", and percent error when one value is the known correct value.