Understanding Percentage Change
Percentage change measures the relative change between an old value and a new value. It's expressed as a percentage and can be positive (increase) or negative (decrease).
Formula
Percentage Change = ((New Value - Old Value) / |Old Value|) x 100
When to Use
- Stock price movements
- Sales growth or decline
- Population changes
- Temperature variations
- Economic indicators
Examples
Example 1: Price increased from $50 to $75
Change = ((75 - 50) / 50) x 100 = 50% increase
Example 2: Sales dropped from 200 to 150 units
Change = ((150 - 200) / 200) x 100 = -25% decrease
Interpreting Results
- Positive percentage = increase
- Negative percentage = decrease
- Zero = no change
Quick Tips
- Double-check your inputs for accurate results
- Use parentheses to clarify order of operations
- Results are rounded — consider significant figures
Frequently Asked Questions
It measures the relative difference between an old and new value as a percentage.
Subtract the old value from the new value, divide by the old value, and multiply by 100.
A negative percentage indicates a decrease.
No, percentage change uses the original value as the base, while percentage difference uses the average.
Yes, if the new value is more than double the old value.