Percentage Increase / Decrease Calculator
This free percentage increase and decrease calculator helps you measure how much a value has grown or dropped compared to its original amount. It is ideal for prices, salaries, statistics, finance, business growth, and everyday comparisons.
What Is Percentage Increase?
Percentage increase shows how much a value has grown relative to its original value. It expresses growth as a percentage rather than an absolute number.
Formula:
Percentage Increase = ((New − Original) ÷ Original) × 100
Example:
If a product price increases from 50 to 65:
((65 − 50) ÷ 50) × 100 = 30% increase
What Is Percentage Decrease?
Percentage decrease measures how much a value has dropped compared to its original amount. It is commonly used for discounts, depreciation, and cost reductions.
Formula:
Percentage Decrease = ((Original − New) ÷ Original) × 100
Example:
If a price drops from 200 to 150:
((200 − 150) ÷ 200) × 100 = 25% decrease
How This Calculator Works
This calculator compares the original value and the new value to determine:
Step 1: Whether the change is an increase or a decrease
Step 2: The exact percentage difference
Step 3: A clear explanation of the result
It automatically applies the correct formula based on the values entered.
Why Percentage Change Matters
Understanding percentage change is important because it allows fair comparisons between different values, regardless of their size.
It is widely used in:
• Business growth analysis
• Stock market performance
• Salary adjustments
• Inflation tracking
• Shopping discounts
• Academic performance
Real-Life Examples
If your salary increases from 2,000 to 2,400:
((2400 − 2000) ÷ 2000) × 100 = 20% increase
If a phone price drops from 900 to 720:
((900 − 720) ÷ 900) × 100 = 20% decrease
Common Mistakes to Avoid
One common mistake is dividing by the new value instead of the original value.
Another mistake is confusing percentage change with absolute change.
Important: A change from 100 to 110 is a 10% increase, not just an increase of 10 units.
Correct: Percentage focuses on relative change, not just absolute difference.
Frequently Asked Questions
Can percentage change be negative?
Yes. A negative result indicates a percentage decrease.
What if the original value is zero?
Percentage change cannot be calculated when the original value is zero.
Can I use decimals?
Yes. Decimal values are fully supported.
Conclusion
Percentage increase and decrease calculations are essential for understanding changes in values over time. This calculator provides instant, accurate results with clear explanations.
Use it for prices, finances, studies, or everyday decisions with confidence.