Percentage Difference Calculator

Compare two values using their average as the percentage-difference base. Enter your own values below to see percentage difference and check the method behind it.

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Your inputs

Change the example values to match your situation.

Your result

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Fill in your inputs and select Calculate.
Your result and breakdown will appear here.

How this calculator works

Percentage difference = absolute difference ÷ average of the two non-negative values × 100.

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What is Percentage Difference Calculator?

Percentage Difference Calculator helps you compare two values using their average as the percentage-difference base.

The main result is percentage difference. The formula, example and assumptions below explain how to interpret it.

How to use Percentage Difference Calculator

Use the example to get familiar with the form, then enter your own figures. Any rates in the example are illustrative. Check the field labels and units before calculating.

  1. Gather first value and second value. Use values from the same situation or reporting period.
  2. Replace the example first value with your own value, then complete the other fields. Check the displayed units.
  3. Select Calculate and read percentage difference. Change one input and calculate again to compare a second scenario. Reset restores the original example.
  • Enter first value, at least 0. Decimals are accepted.
  • Enter second value, at least 0. Decimals are accepted.

Percentage Difference Calculator: a worked example

With the inputs below, the result is 18.181818 % (percentage difference). Follow the example, then replace these illustrative values with your own.

Example inputs and output
Input or outputExample value
First value100
Second value120
Percentage difference18.181818 %

Understanding the Percentage Difference result

The main output is percentage difference, expressed in %. It applies to the inputs and operation you selected.

Displayed results use a readable number of decimal places. When checking a result by hand, keep extra precision until the last step. To compare scenarios, change one input at a time and keep the others fixed.

Percentage Difference Calculator: assumptions and common mistakes

A useful estimate starts with the right inputs. Check the following assumptions and limits before applying the result to your situation.

  • Check the base value, sample definition and chosen operation. Display rounding should come after the calculation.

For wider guidance, visit NIST statistical handbook. The formula and scope of this specific tool are stated on this page.

Percentage Difference Calculator FAQs

What does Percentage Difference Calculator calculate?

Percentage Difference Calculator helps you compare two values using their average as the percentage-difference base. Its main output is percentage difference in %.

What inputs do I need for Percentage Difference Calculator?

You need first value and second value. Use the field labels and units to match your figures to the formula.

Which formula does Percentage Difference Calculator use?

Percentage difference = absolute difference ÷ average of the two non-negative values × 100.

What is a worked example for Percentage Difference Calculator?

Example inputs: First value: 100; Second value: 120. The result is 18.181818 % (percentage difference).

How should I enter first value?

Enter first value, at least 0. Decimals are accepted.

How do I choose second value?

Enter second value, at least 0. Decimals are accepted. The example uses 120; replace it if your circumstances differ.

How should I read percentage difference?

The main output is percentage difference, expressed in %. It applies to the inputs and operation you selected.

Why might my Percentage Difference Calculator result differ from my records?

Check the base value, sample definition and chosen operation. Display rounding should come after the calculation. Differences in entered values, units or rounding can also change the comparison.

Can I compare two scenarios in Percentage Difference Calculator?

Yes. Note your first percentage difference, change first value or another input, and select Calculate again. Editing a field clears the old result so it is not mistaken for a new calculation.

Is Percentage Difference Calculator free, and where are my inputs calculated?

This calculator is free to use without signing in. Its formula runs in your browser; calculator inputs are not sent to a calculation API. The inputs reset to the example values when you reset the form or start a fresh page.