Calculators
Percentage Change Calculator
Measure the percentage increase or decrease between two values.
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When to use percentage change calculator
- Compare this month’s sales with last month’s.
- Measure a price increase or a reduction in expenses.
How it works
Percentage change = (new value − original value) ÷ original value × 100.
Supported inputs and limits
The original value must be greater than zero. A percentage change from zero is undefined. Negative starting values use different conventions and are intentionally rejected.
Common questions
Why are the reverse percentages different?
The starting value changes, so the denominator changes.
What does a negative result mean?
The new value is lower than the original value.
Methodology reviewed 2026-09-09. Processing details and test approach.