Percentage Difference Calculator

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Percentage Difference Calculator

Compare two values as a percentage of their average with a clear side-by-side result panel.

Last updated: March 2026 | By ForgeCalc Engineering

Percentage Difference Solver

Symmetric comparison

Calculation Steps

1.Value 1: 100
2.Value 2: 120
3.Absolute difference = |100 - 120| = 20
4.Average = (100 + 120) / 2 = 110
5.Formula: (absolute difference / absolute average) × 100
6.Calculation: (20 / 110) × 100 = 18.181818%
Percent Difference
18.181818%

Relative difference

What Is Percentage Difference?

Percentage difference compares two values symmetrically by dividing their absolute difference by their average. It is useful when neither value is the clear starting point.

How to Calculate Percentage Difference

  1. Find the absolute difference between the two values.
  2. Compute the average of the two values.
  3. Divide the difference by the absolute average.
  4. Multiply by 100.
difference = |value1 - value2|

Worked Example

Example: 45 and 55 differ by 20% relative to their average.

|45 - 55| / ((45 + 55) / 2) x 100 = 20%

Frequently Asked Questions

What is the difference between percent change and difference?

Percent change has a direction from old to new; percent difference is symmetric.

Can percent difference be negative?

No. The absolute difference is used, so the result is always non-negative.

Does this accept decimals?

Yes. Any finite real values are accepted.

What if one value is zero?

That is allowed as long as the average is not zero.

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