INTERACTIVE TOOL
Percentage change calculator
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How to use this tool
- Enter the original value first.
- Enter the final value using the same unit.
- Read the sign: positive means an increase and negative a decrease.
Formula or method usedPercentage change = (final value − initial value) ÷ |initial value| × 100.
Worked example
Moving from 80 to 100 is a twenty-five percent increase. Returning from 100 to 80 is a twenty percent decrease.
Assumptions and limits
A zero starting value has no defined percentage change.
Frequently asked questions
What happens when the initial value is zero?+
A conventional percentage change is undefined because it would require division by zero.
What happens to my inputs?+
Calculation inputs are processed locally in your browser. Favorites and preferences may be saved on this device. The site may perform separate network requests for live panels; these do not include the values entered into this local calculator. Do not paste secrets into public tools.
How should I check the result?+
A zero starting value has no defined percentage change.