Percentage Change Calculator
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This calculator helps you determine the percentage change between two values. It shows whether the result is an increase or decrease and calculates the exact percentage difference relative to the original value.
Percentage change is one of the most important calculations in finance, business, and everyday life. It is used to track growth, measure losses, analyse performance, and compare data over time.
Use this tool for pricing changes, sales analysis, financial tracking, and performance measurement.
For UK student finance planning, the same old-vs-new percentage idea applies to household income drops—see the Student Finance CYI Calculator (guidance only).
Formula: ((New − Old) ÷ Old) × 100
Result Explanation
The result shows how much the value has changed relative to the original value. A positive result indicates an increase, while a negative result indicates a decrease.
How It Works
The calculator subtracts the original value from the new value, divides the result by the original value, and multiplies by 100.
This produces a relative change expressed as a percentage.
Examples
Example 1: £100 → £120 = 20% increase
Example 2: £80 → £60 = 25% decrease
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FAQ
How do you calculate percentage change?
Subtract old from new, divide by old, multiply by 100.
What does a negative result mean?
It means the value has decreased.
Why can't I calculate from zero?
Because division by zero is undefined.