About this calculator
The Percent Change Calculator measures how much a value has changed from an original value to a new value. It shows both the percentage and the direction, so it is useful for price changes, growth rates, marks, measurements, sales, costs, and before-and-after comparisons.
percent change calculator formula
Percent change uses the original value as the reference point. A positive answer is an increase and a negative answer is a decrease.
- percent change = ((new value - original value) / |original value|) x 100
- change = new value - original value
How to use the percent change calculator
- Enter the original value.
- Enter the new value.
- Subtract original from new to find the change.
- Divide the change by the absolute original value.
- Multiply by 100.
- Read whether the result is an increase or decrease.
Worked examples
Increase from 50 to 75
Input: Original 50, new 75
Calculation: ((75 - 50) / 50) x 100
Result: 50% increase
Decrease from 100 to 80
Input: Original 100, new 80
Calculation: ((80 - 100) / 100) x 100
Result: -20%, a 20% decrease
Increase vs decrease
The sign tells you the direction. Positive means the new value is higher than the original. Negative means the new value is lower.
Why the original value matters
Percent change is measured relative to the starting point. Changing from 50 to 75 is not the same percentage as changing from 75 back to 50.
Percentage calculation note
This calculator is for education, checking, and general planning. Percentage results depend on the inputs and the chosen method, so check whether your question asks for percent change, percent difference, percent error, reverse percentage, or a simple conversion.
- Percent change has direction, but percent difference does not.
- Reverse percentage calculations can be confused with percentage increase or decrease.
- Rounded percentages may not reverse exactly to the original values.
Frequently asked questions
Does this show the working?
Yes. The percentage calculators show the key formula and calculation steps.
What does percent mean?
Percent means per hundred, so 25% means 25 out of 100.
Why do some percentage answers differ?
Different percentage questions use different reference values. Percent change, percent difference, and percent error are not the same.
Can percentages be more than 100?
Yes. A percentage can be above 100 when a value is larger than the reference whole.
Should I round the answer?
Round only to the precision required by your homework, report, invoice, or calculation context.
Related calculators
- Percent Increase Calculator
- Percent Decrease Calculator
- Percentage Calculator