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Percentage Change Calculator

Find the percentage change between two values, whether they went up or down. The percentage change calculator also gives the percentage difference, which people often confuse with it. A rise on its own is the percentage increase calculator. A drop on its own is the percentage decrease calculator.

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Percentage change
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How to use the Percentage Change Calculator

  1. Enter the Original value (A).
  2. Enter the New value (B). Use Swap A and B to reverse them.
  3. Press Calculate. The signed change appears first, with the difference and the percentage difference.

How it works

percentage change = (B − A) ÷ |A| × 100
percentage difference = |A − B| ÷ ((A + B) ÷ 2) × 100

Change is measured from the original value, so its size depends on direction. Percentage difference compares the gap with the average of both values, so it is the same either way round.

Examples

  • 50 → 65 = +30%. The percentage difference is 26.09%.
  • 65 → 50 = −23.08%, even though the gap is the same 15.

50 to 65 in the calculator

Percentage Change Calculator: original value 50, new value 65, percentage change +30%, difference +15, percentage difference 26.086957%
From 50 to 65: change and difference.

The first example: from 50 to 65 is a 30% increase, a difference of 15, and a percentage difference of 26.086957%. This example is one of the automated tests for the tool, so a code change that gives a different answer fails the test run.

Change or difference?

Use percentage change when there is a before and after, such as last year's sales and this year's. Use percentage difference when neither value is the starting point, such as comparing two shops' prices on the same day.

Limitations

  • An original value of 0 has no percentage change, because you cannot divide by zero.
  • Percentage difference is undefined when both values add up to 0.

Read the guide

Calculate a percentage decrease

Measure a drop from the original value, see why a 25% fall needs a 33.3% rise to recover, and how two discounts combine.

Frequently asked questions

How do I calculate percentage change?

Subtract the old value from the new value, divide by the old value, and multiply by 100.

Why is a rise from 50 to 65 not the same as a fall from 65 to 50?

Because each is measured from a different starting value: 15 is 30% of 50 but 23% of 65.

What is the difference between percentage change and percentage difference?

Change is measured from the original value. Difference is measured from the average of both.

Often used together with Percentage Change Calculator.