1. What is Percentage Change?

Percentage change measures the degree of change over time. It's used to compare an old value to a new value, expressing the difference as a percentage of the old value. Positive values indicate an increase, while negative values indicate a decrease.

2. How Does the Calculator Work?

The calculator uses the percentage change formula:

Explanation: The formula calculates the difference between new and old values, divides by the old value to get a relative change, then multiplies by 100 to convert to a percentage.

3. Importance of Percentage Change

Details: Percentage change is widely used in finance, economics, statistics, and general data analysis. It allows comparison between different scales and magnitudes by standardizing changes as percentages.

4. Using the Calculator

Tips: Enter both old and new values. The calculator will automatically determine if it's an increase or decrease and display the percentage change. Note that the old value cannot be zero.

5. Frequently Asked Questions (FAQ)

Q1: What does a negative percentage change mean?
A: A negative percentage change indicates a decrease from the old value to the new value.

Q2: Why can't the old value be zero?
A: Division by zero is mathematically undefined. When the old value is zero, percentage change cannot be calculated.

Q3: How is percentage change different from percentage difference?
A: Percentage change compares two values over time (before/after), while percentage difference compares two different values at the same time.

Q4: What's considered a significant percentage change?
A: This depends entirely on context. In finance, 5% might be significant for stocks, while in population growth, 1% might be significant.

Q5: Can percentage change exceed 100%?
A: Yes. A change from 10 to 30 is a 200% increase (20/10 × 100). Decreases can't exceed -100% (complete elimination).