Percent Change Calculator
Calculate percentage increase or decrease between an old value and a new value.
Calculator updated
Use this page to get a quick answer, then check the formula and example before making an important decision.
- The main result from your inputs
- Formula used for the calculation
- Worked example and common mistakes
- Related calculators for the next step
Formula
Percent Change = (new value - old value) / old value × 100.
100 to 120 is a 20% increase.
Enter the known values and apply Percent Change = (new value - old value) / old value × 100.. Keep signs, decimal places, and the order of operations consistent with the problem you are checking.
Use the Percent Change Calculator to solve or verify a math problem, compare inputs, and check a manual calculation.
Common math errors include using the wrong operation, dropping a negative sign, rounding intermediate steps too early, and confusing percentages with decimal values.
Examples
Inputs
Old value, New value
Keep units and time periods consistent.Formula
Percent Change = (new value - old value) / old value × 100.
Use the formula to verify the result.What the result means
Calculate percentage increase or decrease between an old value and a new value.
Change one input at a time to compare scenarios.How to Calculate Percent Change Manually
Start with the values requested in the form, keep the units consistent, and apply this formula: Percent Change = (new value - old value) / old value × 100.
The calculator above follows the same logic, then formats the answer so you can quickly compare inputs, copy the result, and check the related tools if your task has another step.
When to Use This Calculator
- Solve a homework or everyday math problem
- Check a manual calculation
- Compare different inputs
- Verify a formula step
How It Works
- Enter Old value, New value.
- Confirm signs, units, and decimal values.
- Compare the result with the formula shown on the page.
Common Mistakes
- Using the wrong operation
- Dropping a negative sign
- Rounding intermediate steps
- Confusing percentages and decimals
Related Calculators
More Percentages & ratios tools
Continue the same workflow with closely related calculators.
Frequently Asked Questions
What does the Percent Change Calculator do?
Calculate percentage increase or decrease between an old value and a new value.
Is this result an estimate?
Yes. The calculator follows the formula shown on the page. Verify important decisions with a qualified professional where needed.
Can I use this on mobile?
Yes. The calculator is designed to work on phones, tablets, and desktop screens.