Percentage Change Calculator — Change and Difference
Compare an original and new value to see the absolute difference, percentage change, and symmetric percentage difference.
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How to use it
Enter the old and new values to see the percentage change and difference.
Good to know
Percentage change uses the old value as the base. Percentage difference uses the average of both.
Separate the direction from the size of a change
Enter the old value first and the new value second. From 80 to 100, the tool reports an Increase of 25%, a difference of 20, and a percentage difference of 22.22%. Percentage change uses the first value as the base: (100 − 80) ÷ 80 × 100.
Choose the measure that answers the question
Percentage difference uses the average of the two values as its base, so it is symmetric but answers a different question. A decrease from 100 to 80 is −20%, while an increase from 80 to 100 is +25%. The tool performs arithmetic only; check units, baselines, rounding, and domain-specific reporting conventions before using a figure in a financial or scientific claim.
Frequently asked questions
How do I calculate percentage increase?
Subtract the old value from the new value, divide by the old value, and multiply by 100. 80 to 100 is a 25% increase.
What is the difference between percentage change and percentage difference?
Change compares against the starting value. Difference compares two values without a direction, using their average.
Can I calculate a percentage decrease?
Yes. A new value lower than the old value gives a negative change, shown as a decrease.