How do I calculate percentage difference?

Find the absolute difference between the two values, calculate their average, then divide the difference by that average and multiply by 100. For example, the difference between 80 and 100 is 20, the average is 90, and 20 ÷ 90 × 100 = 22.222222%.

What is the formula for percentage difference?

The standard formula is (|first value - second value| ÷ ((first value + second value) ÷ 2)) × 100. It compares two values without choosing one of them as the baseline.

What is the difference between percentage difference and percentage change?

Percentage change uses one starting value as the baseline, so direction matters. Percentage difference is symmetrical, which makes it useful when you only care about the size of the gap between two values.

Percentage difference calculator

Percentage Difference Calculator

Use this percentage difference calculator to compare two values without picking a starting baseline first. It shows the percentage difference, the absolute gap, and the average used in the formula.

Percentage difference

22.222222%

The percentage difference between 80 and 100 is 22.222222% (20 over an average of 90).

Absolute gap

Average used

How it works

Compare the size of the gap, not the direction

Percentage difference is useful when you want to compare two values but do not want to treat one of them as the official baseline. It focuses on how far apart the numbers are relative to their average.

Formula

(|first value - second value| ÷ ((first value + second value) ÷ 2)) × 100

First find the absolute gap, then divide that gap by the average of the two values, then convert the result to a percentage.

Worked example

1. Start with 80 and 100.
2. Find the absolute gap: |80 - 100| = 20.
3. Find the average: (80 + 100) ÷ 2 = 90.
4. Divide 20 by 90 and multiply by 100 to get 22.222222%.

When people use this

Data comparison: compare two measurements without naming a baseline.
Reports: compare two teams, suppliers, or estimates symmetrically.
Quality control: measure how far two readings differ.
Benchmarks: compare actual vs expected values when you care about the gap size.

Related calculators

Keep moving through the percentage cluster

Percentage difference complements percentage change. Use change when you have a real before-and-after baseline, and use difference when you only care about the symmetric gap between two values.

Live now

Percentage Difference Calculator

Keep moving through the percentage cluster

Percentage Change Calculator

Percentage Increase Calculator

Percentage Decrease Calculator

Percentage Calculator