1. What is Percentage Change?

Percentage change measures the relative difference between an old value and a new value, expressed as a percentage. It shows how much a quantity has increased or decreased compared to its original amount.

2. How Does the Calculator Work?

The calculator uses the percentage change formula:

Where:

• New Value — The current or final value
• Old Value — The original or initial value

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

3. Practical Applications

Details: Percentage change is widely used in finance (stock prices, inflation), business (sales growth), science (experimental results), and everyday life (price comparisons).

4. Using the Calculator

Tips: Enter both old and new values. The calculator will show the percentage increase or decrease. Note that the old value cannot be zero (division by zero is undefined).

5. Frequently Asked Questions (FAQ)

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

Q2: How is percentage change different from percentage difference?
A: Percentage change compares two values over time (before/after), while percentage difference compares two simultaneous values.

Q3: What if my old value is zero?
A: Percentage change is undefined when the old value is zero, as it would require division by zero.

Q4: Can percentage change be more than 100%?
A: Yes, a percentage change can exceed 100% when the new value is more than double the old value.

Q5: How do I interpret a percentage decrease?
A: A percentage decrease shows what portion of the original amount was lost. For example, a 20% decrease means the new value is 80% of the original.