Math

Percentage Difference Calculator

Compare two values when neither is the ‘original’.

By TheCalcTools Updated Formula checked and tested

Your numbers

Your results

Percentage difference
Percentage difference
—
Absolute difference
—
Average of the two
—

Percentage Difference Calculator by TheCalcTools

How the Percentage Difference Calculator works

Enter the two values you want to compare.

Divide the absolute difference by the average of their absolute values.

Multiply by 100 for a percentage.

The formula

Percentage difference = |a − b| ÷ ((|a| + |b|) ÷ 2) × 100

Worked example

Using the default values shown in the calculator:

First value80
Second value120
  1. |80 − 120| = 40.00; average = 100.00.
  2. Difference = 40 ÷ 100 = 40.00%.

Result:

Percentage difference40.00%
Absolute difference40.00
Average of the two100.00

Frequently asked questions

How is it different from percent change?

Percent change uses the starting value as the base and has a direction. Percentage difference uses the average, so it is symmetric: swapping a and b gives the same answer.

When should I use it?

When comparing two measurements of equal standing, such as two labs’ results, rather than before and after.

Sources and further reading

Percentage Change CalculatorFind the percentage change from an old value to a new value Percentage CalculatorChoose the question you want answered, enter two numbers, and get the percentage result… Ratio Simplifier CalculatorSimplify a ratio A : B to its lowest terms Percent Error CalculatorEnter the measured value and the accepted value Reverse Percentage Calculator (Find the Original Value)Enter the final amount and the percentage that was added or taken off

More in Math · All calculators

This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.