Percent change calculator
Enter the old and new values to see how much they changed as a percentage. Useful for prices, sales and weight tracking.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter old value and new value.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Percent change = ((new - old) ÷ |old|) × 100
Example
Inputs: Old value = 50, New value = 75. Result: Percent change: 50%; Difference: 25; Direction: Increase.
Limits and caveats
- We divide by the absolute old value so the sign stays meaningful for negative numbers.
- A 50% rise followed by a 50% fall does not return you to the start, because each percentage uses a different base.
Questions about this tool
A price rose from 50 to 75. What is the percentage increase?
The difference is 25. Divide by 50 and multiply by 100 to get a 50% increase.
How is percent change different from percentage points?
If a rate moves from 10% to 15%, that is 5 percentage points but a 50% change.
Why does it fail when the old value is zero?
Percent change divides by the old value, and division by zero is undefined.