Percentage Cost Increase Calculator
Calculate the percentage change (increase or decrease) between an original cost/value and a new cost/value.
Enter the **Original Cost** and the **New Cost** below. The calculator will determine the percentage difference relative to the original cost. Ensure your values are in the same currency or units.
Enter Costs
Understanding Percentage Increase/Decrease
What is Percentage Change?
Percentage change measures the relative difference between an old (original) value and a new value. It is expressed as a percentage of the original value. It can be a percentage increase (if the new value is greater than the original) or a percentage decrease (if the new value is less than the original).
Formula for Percentage Change
The formula is straightforward:
Percentage Change = ((New Value - Original Value) / Original Value) * 100
If the result is positive, it's a percentage increase. If the result is negative, it's a percentage decrease.
Example Calculation
EX: An item's price increased from $50 to $60. Calculate the percentage increase.
Original Value = 50, New Value = 60
Difference = New Value - Original Value = 60 - 50 = 10
Percentage Change = (Difference / Original Value) * 100 = (10 / 50) * 100 = 0.2 * 100 = 20
Result: The price increased by 20%.
EX: A salary decreased from $800 to $700. Calculate the percentage change.
Original Value = 800, New Value = 700
Difference = New Value - Original Value = 700 - 800 = -100
Percentage Change = (Difference / Original Value) * 100 = (-100 / 800) * 100 = -0.125 * 100 = -12.5
Result: The salary changed by -12.5% (a 12.5% decrease).
Percentage Change Examples
Click on an example to see the step-by-step calculation:
Example 1: Standard Price Increase
Scenario: A loaf of bread cost $2.00 last year and costs $2.50 this year. What is the percentage increase?
1. Known Values: Original Cost = $2.00, New Cost = $2.50
2. Difference: $2.50 - $2.00 = $0.50
3. Formula: Percentage Change = (Difference / Original Cost) * 100
4. Calculation: ($0.50 / $2.00) * 100 = 0.25 * 100 = 25
5. Result: 25% Increase.
Conclusion: The price of bread increased by 25%.
Example 2: Price Decrease (Discount)
Scenario: A shirt originally priced at $30 is now on sale for $21. What is the percentage change?
1. Known Values: Original Cost = $30, New Cost = $21
2. Difference: $21 - $30 = -$9
3. Formula: Percentage Change = (Difference / Original Cost) * 100
4. Calculation: (-$9 / $30) * 100 = -0.3 * 100 = -30
5. Result: -30% Change (a 30% Decrease).
Conclusion: The shirt price decreased by 30%.
Example 3: Stock Value Increase
Scenario: A stock was worth $15 per share and is now worth $18 per share. What is the percentage increase?
1. Known Values: Original Value = $15, New Value = $18
2. Difference: $18 - $15 = $3
3. Formula: Percentage Change = (Difference / Original Value) * 100
4. Calculation: ($3 / $15) * 100 = 0.2 * 100 = 20
5. Result: 20% Increase.
Conclusion: The stock value increased by 20%.
Example 4: Enrollment Decrease
Scenario: A course had 200 students enrolled last semester but only 180 this semester. What is the percentage change?
1. Known Values: Original Enrollment = 200, New Enrollment = 180
2. Difference: 180 - 200 = -20
3. Formula: Percentage Change = (Difference / Original Enrollment) * 100
4. Calculation: (-20 / 200) * 100 = -0.1 * 100 = -10
5. Result: -10% Change (a 10% Decrease).
Conclusion: Enrollment decreased by 10%.
Example 5: Website Traffic Increase
Scenario: Monthly website visits went from 5,000 to 7,500. What is the percentage increase?
1. Known Values: Original Visits = 5,000, New Visits = 7,500
2. Difference: 7,500 - 5,000 = 2,500
3. Formula: Percentage Change = (Difference / Original Visits) * 100
4. Calculation: (2,500 / 5,000) * 100 = 0.5 * 100 = 50
5. Result: 50% Increase.
Conclusion: Website traffic increased by 50%.
Example 6: Energy Consumption Change
Scenario: Last month's energy bill was $150, this month's is $130. What is the percentage change?
1. Known Values: Original Cost = $150, New Cost = $130
2. Difference: $130 - $150 = -$20
3. Formula: Percentage Change = (Difference / Original Cost) * 100
4. Calculation: (-$20 / $150) * 100 ≈ -0.1333 * 100 = -13.33
5. Result: ≈ -13.33% Change (a 13.33% Decrease).
Conclusion: Energy consumption cost decreased by about 13.33%.
Example 7: Test Score Improvement
Scenario: A student scored 60 on the first test and 75 on the second. What is the percentage increase in their score?
1. Known Values: Original Score = 60, New Score = 75
2. Difference: 75 - 60 = 15
3. Formula: Percentage Change = (Difference / Original Score) * 100
4. Calculation: (15 / 60) * 100 = 0.25 * 100 = 25
5. Result: 25% Increase.
Conclusion: The student's score increased by 25%.
Example 8: Population Growth
Scenario: A town's population grew from 10,000 to 10,500 in a year. What is the percentage growth?
1. Known Values: Original Population = 10,000, New Population = 10,500
2. Difference: 10,500 - 10,000 = 500
3. Formula: Percentage Change = (Difference / Original Population) * 100
4. Calculation: (500 / 10,000) * 100 = 0.05 * 100 = 5
5. Result: 5% Increase.
Conclusion: The town's population grew by 5%.
Example 9: Inventory Reduction
Scenario: A store had 500 units of an item in stock and now has 420 units. What is the percentage change in inventory?
1. Known Values: Original Inventory = 500, New Inventory = 420
2. Difference: 420 - 500 = -80
3. Formula: Percentage Change = (Difference / Original Inventory) * 100
4. Calculation: (-80 / 500) * 100 = -0.16 * 100 = -16
5. Result: -16% Change (a 16% Decrease).
Conclusion: Inventory decreased by 16%.
Example 10: Website Conversion Rate Increase
Scenario: A website's conversion rate increased from 2.5% to 3.2%. What is the percentage increase in the rate?
1. Known Values: Original Rate = 2.5, New Rate = 3.2
2. Difference: 3.2 - 2.5 = 0.7
3. Formula: Percentage Change = (Difference / Original Rate) * 100
4. Calculation: (0.7 / 2.5) * 100 = 0.28 * 100 = 28
5. Result: 28% Increase.
Conclusion: The conversion rate increased by 28%.
Frequently Asked Questions about Percentage Change
1. What is percentage increase?
Percentage increase is the relative amount an original value has grown, expressed as a percentage of that original value. It occurs when the new value is higher than the original value.
2. What is percentage decrease?
Percentage decrease is the relative amount an original value has shrunk, expressed as a percentage of that original value. It occurs when the new value is lower than the original value.
3. What is the formula used by this calculator?
The calculator uses the standard formula: `((New Value - Original Value) / Original Value) * 100`.
4. Can this calculator handle both increases and decreases?
Yes. If the new value is higher, the result will be positive (an increase). If the new value is lower, the result will be negative (a decrease).
5. What happens if the original cost is zero?
A percentage change from zero is mathematically undefined. If you enter 0 as the original cost, the calculator will show an error because division by zero is not possible and a percentage relative to zero is not a meaningful concept in this context.
6. What if the new cost is zero?
If the original cost is a positive number and the new cost is zero, the calculator will correctly report a -100% change (a 100% decrease), indicating that the value has dropped completely to zero.
7. Do the units matter for the percentage change?
As long as you use the *same* consistent unit for both the Original Cost and the New Cost (e.g., both in USD, both in meters, both in units), the percentage change will be correct because the units cancel out in the division.
8. How is percentage change different from the absolute change?
Absolute change is the simple difference (New Value - Original Value). Percentage change is the *relative* difference, showing this change as a proportion of the original value, multiplied by 100 to make it a percentage. Percentage change provides context about the magnitude of the change compared to where it started.
9. Is this tool useful for tracking inflation?
Yes, percentage change is the core calculation used to measure inflation, which is the percentage increase in the price of goods and services over a period.
10. How is this used in finance?
Percentage change is widely used in finance to calculate returns on investments, compare price movements of stocks or assets, analyze profit margins, and evaluate economic indicators.
