Percentage Change Calculator
Calculates the percentage change between an old and a new value.
Enter Values
How to use this calculator
- Enter the original (from) value and the new (to) value.
- Press Calculate for the percentage change.
How it works
Percentage change = (new − old) ÷ old × 100. A positive result is an increase and a negative result is a decrease.
Worked example
100 → 150. (150 − 100) ÷ 100 × 100 = +50%.
Common mistakes
- Dividing by the new value instead of the original — percent change is relative to the starting number.
- Dropping the sign; a negative result means a decrease.
Frequently asked questions
How do I calculate percentage change?
Percentage change = (new − old) ÷ old × 100. From 80 to 100 is (100 − 80) ÷ 80 × 100 = 25% increase.
What's the difference between change and difference?
Percentage change is relative to the original value; percentage difference compares two values against their average, so they give different answers.
Why divide by the old value, not the new one?
Percentage change measures the change relative to the starting point, so the original (old) value is always the base.
Related tools
- Percentage Calculator
- Discount Calculator
- Markup Calculator
- Basic Calculator
- Percentage Decrease Calculator
- Percentage Difference Calculator
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Cite this tool
Zerdly. (2026). Percentage Change Calculator. Retrieved from https://www.zerdly.com/tools/percentage-change-calculator/
Tip: Enter any known values to calculate the remaining results.
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