Put Old and New Value to Get Percentage Calculator

Calculating percentage change between two values is a fundamental skill used in finance, science, and everyday life. This calculator helps you determine whether a value has increased or decreased, and by what percentage, by simply entering the old and new values.

How to Use This Calculator

Using our percentage calculator is straightforward:

Enter the original (old) value in the first field
Enter the new value in the second field
Click the "Calculate" button
Review the percentage change result

The calculator will show you both the percentage change and whether it's an increase or decrease. You can also view a visual representation of the change.

Percentage Change Formula

The formula for calculating percentage change is:

Percentage Change = [(New Value - Old Value) / Old Value] × 100

Where:

New Value is the current value
Old Value is the original value

A positive result indicates an increase, while a negative result indicates a decrease.

Worked Examples

Example 1: Price Increase

If a product's price increases from $50 to $75:

Percentage Change = [(75 - 50) / 50] × 100 = 50%

This is a 50% increase in price.

Example 2: Population Decrease

If a city's population decreases from 10,000 to 8,000:

Percentage Change = [(8,000 - 10,000) / 10,000] × 100 = -20%

This is a 20% decrease in population.

Interpreting Results

When using this calculator, consider these interpretation guidelines:

Positive percentages indicate growth or improvement
Negative percentages indicate decline or reduction
Small percentage changes may not be statistically significant
Context matters - a 10% increase in sales might be excellent for one business but poor for another

Remember that percentage changes are relative to the original value. A small absolute change can represent a large percentage change if the original value is small.

Frequently Asked Questions

What is the difference between percentage change and percentage difference?: Percentage change measures the relative change from an original value, while percentage difference compares two values without considering their original context.
How do I calculate percentage change when the old value is zero?: Percentage change is undefined when the old value is zero because you cannot divide by zero. In this case, the change is simply the new value.
Can I use this calculator for financial returns?: Yes, this calculator is perfect for calculating investment returns, price changes, or any other scenario where you need to measure percentage change.
Is percentage change the same as percentage increase?: No, percentage increase specifically refers to positive changes. Percentage change can be positive (increase) or negative (decrease).
How accurate is this calculator?: The calculator uses standard percentage change formulas and provides precise results based on the values you enter.