Enter the starting value and the final value you want to compare.

The Percentage Change Calculator measures how much a value has increased or decreased relative to its original amount.

### Understanding the Calculation

The calculator uses the following formula:

Percentage Change = ((Final Value - Starting Value) / Starting Value) × 100

A positive result indicates a percentage increase, while a negative result indicates a percentage decrease. A result of zero means the value has not changed.

The calculator also determines the numerical difference between the starting and final values.

### Example

Suppose an item originally costs $80 and its price increases to $100.

The numerical increase is $20.

Percentage Change = ((100 - 80) / 80) × 100 = 25%

The item's price has therefore increased by 25%.

If the starting value is $100 and the final value is $80, the result is a 20% decrease.

### Important Considerations

Percentage change is measured relative to the starting value. Reversing the two values can produce a different percentage.

For example, increasing a value from 80 to 100 represents a 25% increase, while decreasing it from 100 to 80 represents a 20% decrease.

When the starting value is zero, the standard percentage change formula is undefined because division by zero is not possible.

Negative starting values may also require additional interpretation depending on the context.

This calculator is intended for educational and general mathematical purposes. It can help compare changes in prices, expenses, revenue, investments, measurements, and other numerical values.