Quick answer
How do you calculate Percentage Change?
Use Percentage change = (New value - Original value) / Original value x 100. Enter the matching values above to calculate the result instantly.
What it measures
Understanding Percentage Change
Calculate the percentage increase or decrease from an original value to a new value. Percentage change scales the absolute difference by the original value, making changes across different starting sizes easier to compare.
Interpretation
What the result means
A positive result indicates an increase from the original value; a negative result indicates a decrease.
Action
How to use it
Keep units, time periods, and definitions consistent and report the starting value alongside the percentage to preserve context.
Limits
What it leaves out
The calculation is undefined when the original value is zero, and reversing a change does not produce equal opposite percentages.
The math
Percentage Change formula
Worked example
Example calculation
- Calculation
- (100 - 80) / 80 x 100
- Result
- 25% increase
Step by step
How to use this calculator
- 1Enter original value, new value.
- 2Keep every input on the same time period and measurement basis.
- 3Review the result, then change one assumption at a time to test scenarios.
Decision support
When this calculator is useful
- Price changes
- Performance comparisons
- Growth analysis
Common questions
Frequently asked questions
Which inputs should I use for Percentage Change?
Use original value, new value, measured from the same source and period. Include only values that match the definitions shown beside each field.
Why might two Percentage Change calculations differ?
The systems or accounting policies may define original value, new value differently. Compare the time period, scope, source, and treatment of exceptional items before comparing results.
How often should I recalculate Percentage Change?
Recalculate when any input changes materially and on the same reporting cadence used for the decision. Save the source and date of each input so the trend remains comparable.
Can I use Percentage Change by itself?
No single metric captures the full decision. Use the result with the related measures, assumptions, and limitations shown on this page.
Calculation reviewed: 2026-06-18. CalcPilot uses the formula shown above and tests representative values during the production build. See our methodology and correction policy.
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