Math Calculators
Percentage Change Calculator
Calculate the percentage increase or decrease between an old value and a new value. Useful for tracking price changes, salary growth, or investment returns.
Formula Used
((New Value β Old Value) Γ· |Old Value|) Γ 100
About This Calculator
What It Does
This calculator measures the percentage increase or decrease between an old value and a new value. Enter two numbers and it instantly shows the change as a percentage, plus whether it's an increase or decrease. Useful for tracking growth, decline, or change over time in any context.
Worked Example
Example 1 β Increase: Old salary was 100 units, new salary is 120 units. ((120 β 100) Γ· 100) Γ 100 = +20%. A 20% increase. Example 2 β Decrease: An item priced at 80 units is now 60 units. ((60 β 80) Γ· 80) Γ 100 = β25%. A 25% decrease. Example 3 β Zero to positive: A value goes from 0 to 50. Since division by zero is undefined, percentage change from zero is treated specially β any positive result from zero is a 100% increase by convention.
Real-World Usage
Track salary raises and negotiate pay increases. Measure investment returns and portfolio performance. Monitor price changes in goods, services, or stocks. Calculate year-over-year business growth or decline. Weight loss or gain expressed as a percentage of starting weight. Compare population changes, test scores, or any metric over time.
Local Context
Percentage change works consistently across all currencies and regions. The formula is the same worldwide. When comparing financial metrics across countries, pair this with the currency converter to standardize values in the same currency before calculating the percentage change.
Last reviewed: May 2026.
Frequently Asked Questions
What does a negative percentage change mean?
A negative result means the value has decreased. For example, going from 100 to 80 is a 20% decrease.
How is percentage change different from percentage difference?
Percentage change compares an old value to a new value over time. Percentage difference compares two values without regard to direction or time.
Can this calculator handle negative old values?
Yes, but the result becomes less intuitive. We use the absolute value of the old value as the denominator to avoid misleading results.