Percentage Difference Calculator

Use this percentage difference calculator to compare two values when neither value is the original or baseline. It calculates percentage difference, absolute difference, and the average of the two values.

Value A
Value B

How to Use the Percentage Difference Calculator

Enter two values to compare their difference relative to their average.

Practical Example

Comparing 80 and 100 gives a percentage difference of about 22.22%.

Factors That Affect the Result

Percentage difference is symmetric, unlike percentage change. Very small average values can produce large percentages.

Frequently Asked Questions

Does input order matter?

No. Percentage difference is symmetric.

Is this the same as percentage change?

No. Percentage change uses an original value as the reference.

Can the result exceed 100%?

Yes, depending on the values.

Related Tools

Percentage Difference vs Percentage Change

Percentage difference is designed to compare two values without treating either one as the original baseline. A common formula is |A − B| ÷ ((A + B) ÷ 2) × 100. For example, comparing 90 and 110 gives an absolute difference of 20 and an average of 100, so the percentage difference is 20%. This is different from percentage change, which divides by an original value and therefore depends on direction. Percentage difference is useful for comparing two measurements, experimental results or estimates that have equal status. If one value clearly represents the starting point and the other represents a later value, percentage change is usually the better metric. Values near zero can produce very large percentages, so always interpret the result together with the actual numerical difference and the context of the data.

When Percentage Difference Is Appropriate

Percentage difference is useful when comparing two measurements, estimates or experimental results without designating either one as the baseline. It uses the absolute difference divided by the average magnitude of the two values. For a true before-and-after comparison, percentage change is usually the more appropriate measure.