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math tool

Percentage Change Calculator

Calculate percentage increase or decrease between two numbers instantly.

Calculate the percent difference between two values.

resultslive
Change

20%

Difference

20

Result Type

Increase

About the percentage change calculator

How this calculator works

Percentage change compares how far a new value has moved relative to the starting value. That makes it more useful than just looking at the raw difference on its own.

This page is focused on before-and-after comparisons, so it keeps the inputs and explanation simpler than the broader percentage calculator.

Where it is useful

The tool is useful for revenue changes, traffic trends, score changes, pricing shifts, and KPI snapshots.

A dedicated page also makes it easier to send people directly to the increase/decrease workflow when that is the exact task they need.

  • Measure price increases and discount differences.
  • Compare performance metrics across weeks or months.
  • Check growth or decline for traffic, sales, and production counts.

Example calculations

3 examples
example

100 to 120

20% increase

example

250 to 200

20% decrease

example

-100 to -80

20% increase

negative baseline

Common uses

3 ideas
  • Measure price increases and discount differences.
  • Compare performance metrics across weeks or months.
  • Check growth or decline for traffic, sales, and production counts.

FAQ

3 answers

What formula is used for percentage change?

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

Why does the old value need to be non-zero?

The old or original value cannot be zero because percentage change divides by that starting value.

Does the calculator show the absolute difference too?

Yes. The result card shows the raw difference as well as the percentage increase, decrease, or no-change result.

Related tools

5 links