Power Calculators

↔️ Percentage Difference Calculator

Compare two values using percentage difference based on the average of their magnitudes.

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Fill in the details and click Calculate to see your results.


Also available in our Android app, with charts and full breakdown tables.

📘 About the Percentage Difference

Percentage difference is useful when comparing two values without designating one as the original value.

The denominator is the average of the absolute values of the two inputs.

🧮 Formula

Absolute difference
Difference = |A − B|
Average magnitude
Average magnitude = (|A| + |B|) ÷ 2
Percentage difference
Percentage difference = |A − B| ÷ Average magnitude × 100

Where

  • A = first value
  • B = second value
Use absolute values when the quantities can be negative and a symmetric comparison is intended.

✏️ Worked example

Compare 100 and 120

You enter
Value A100
Value B120
You get
Absolute Difference20
Average Magnitude110
Percentage Difference18.18%

The percentage difference is 18.18%.

Try this example →

🧭 How to use this calculator

What you enter

  • Value A
  • Value B

What you get

  • Absolute Difference
  • Average Magnitude
  • Percentage Difference

💡 Percentage difference versus percentage change

  • Percentage difference is symmetric.
  • Percentage change uses an original value as the reference.
  • Use percentage difference when neither value is the baseline.

❓ Frequently asked questions

What is the formula for percentage difference?

Take the absolute difference between the values, divide by their average magnitude, then multiply by 100.

Is percentage difference symmetric?

Yes. Swapping the two values gives the same result.