Calculator Problems

How to Calculate Percent Difference

Percent difference compares two values relative to their average. It is useful when neither value is treated as the original baseline, such as comparing two measurements or results.

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Step-by-step

Record both values using compatible units.
Find the absolute difference between the values.
Calculate the average of the two values.
Divide the absolute difference by the average and multiply by 100.
Check whether the question asks for percent difference or change from a baseline.

Percent difference formula

Percent difference = |A − B| ÷ ((A + B) ÷ 2) × 100, when the standard average-based definition is appropriate and the average is non-zero.

Percent difference versus percent change

Percent change uses an original value as the baseline. Percent difference commonly treats both values symmetrically by comparing their absolute difference with their average.

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Use the relevant online utility, check the result, and continue with your development workflow.

Open Percent Difference Calculator →Open Percentage Change Calculator →

FAQ

Frequently asked questions

Can percent difference be negative?

The standard absolute-difference formula produces a non-negative result. A signed comparison may instead be measuring percentage change.

What if the average of the two values is zero?

The standard formula is undefined when its denominator is zero. Review the values and choose a comparison method suited to that case.