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.

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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.

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.

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 the Percentage Change Calculator.