Calculation details
Planning estimate only, not financial, tax, or legal advice. Verify assumptions and current rules before making decisions.
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What does this calculator estimate?
Percent change compares a new value to an old one as a percentage of the original.
- Positive = increase, negative = decrease.
- Divides by the original value.
- Used in prices, salaries, and portfolio returns.
What does this calculator estimate?
How this calculator works
Formula
Percent change = (new − old) ÷ |old| × 100.
Worked example
50 → 65 is a +30% change; 65 → 50 is a −23.1% change.
Assumptions to verify
- Standard geometric or arithmetic definitions apply.
- Inputs use the units you choose.
- Results are estimates, not professional advice.
Frequently asked questions
Cite this tool
BoringToolsKit. “Percentage Change Calculator.” boringtoolskit.com/percentage-change-calculator/ (reviewed 2026-08-27). Free to reference in articles, syllabi, and answer posts with a link.
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