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Percentage Change Calculator

Compare an original number with a new one and see the percent change. From 80 to 100 is a 25% rise; 100 back to 80 is a 20% drop. An original of 0 is rejected.

What is Percentage Change Calculator?

A percentage change calculator shows how much a number increased or decreased relative to its starting value.

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Percentage Change Calculator – Increase and Decrease — Tools Star Hub

What this tool does

Compare an original number with a new one and see the percent increase or decrease. Use it when a price, a score, or a measurement moved and you need the size of that move. Going from 80 to 100 is a 25% increase, while 100 back to 80 is a 20% decrease, because the starting numbers differ.

How to use

  1. Enter the original value and the new value.
  2. Press Calculate to see the percentage change.
  3. A positive result is an increase. A negative result is a decrease.

Examples

  • 80 to 100

    The value rose by 20, which is a 25% increase.

  • 100 to 80

    The value fell by 20, which is a 20% decrease.

How it works

Percentage change is (new − original) ÷ original × 100. Going up 25% and then down 20% are not the same size of change, because the starting points are different.

Limitations

An original value of 0 is rejected, because the change is divided by that starting number. When both values are 0, the result is 0%. This page does not find a percent of a number or a discounted price.

See the disclaimer for what these tools do not cover.

FAQ

Is the Percentage Change Calculator free?
Yes. Comparing an original value with a new value to get the percent increase or decrease is free, and no account is required.
Why can’t I use 0 as the original value?
Dividing by zero is undefined. If both values are 0, the change is 0%. Any other new value from 0 cannot be expressed as a finite percentage.
Is my input sent to a server?
No. Both values are used only for the division on this page. Nothing is uploaded or stored.
What is the formula for percentage change?
Percentage change = (new value − original value) ÷ original value × 100. A positive result is an increase and a negative result is a decrease.
Why is a rise from 80 to 100 not the same as a drop from 100 to 80?
The change is divided by the starting number. 20 out of 80 is a 25% rise, while 20 out of 100 is a 20% drop.

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Helpful guides

Guide

How to Calculate Percentage

How to calculate a percentage: X% of a number, a number as a percent of another, and percent increase or decrease.

Read guide