Percentage Change Calculator
Calculate percentage increases, decreases, and changes between values
Value Comparison
Change Analysis
Enter original and new values to calculate percentage change
Understanding Percentage Change
What is Percentage Change?
Percentage change measures the relative difference between two values, expressed as a percentage of the original value. It's a fundamental concept used in finance, economics, statistics, and everyday life to compare changes over time or between different quantities.
Formula:
Percentage Change = ((New Value - Original Value) ÷ |Original Value|) × 100%
Note: Use absolute value of original value to handle negative numbers correctly
Types of Changes
Percentage change can be positive, negative, or zero, each indicating different types of changes in the data being analyzed.
- •Positive Change: New value is greater than original (increase)
- •Negative Change: New value is less than original (decrease)
- •No Change: New value equals original (0% change)
- •Large Changes: Changes over 100% indicate doubling or more
Common Percentage Changes
| Scenario | Original | New | Change | Percentage |
|---|---|---|---|---|
| Price Increase | $100 | $120 | +$20 | +20% |
| Stock Drop | $50 | $40 | -$10 | -20% |
| Population Growth | 1,000 | 1,050 | +50 | +5% |
| Salary Cut | $60,000 | $54,000 | -$6,000 | -10% |
| Investment Double | $1,000 | $2,000 | +$1,000 | +100% |
| No Change | 75 | 75 | $0 | 0% |
Real-World Applications
Finance & Investing
Track investment performance
- • Stock price changes
- • Portfolio returns
- • Interest rate changes
- • Revenue growth
Business Analytics
Measure business metrics
- • Sales growth
- • Customer acquisition
- • Market share changes
- • Product performance
Economics
Economic indicators
- • Inflation rates
- • GDP growth
- • Employment changes
- • Price indices
Science & Research
Experimental results
- • Treatment effectiveness
- • Population changes
- • Environmental metrics
- • Clinical trials
Personal Finance
Budget management
- • Expense tracking
- • Savings growth
- • Debt reduction
- • Income changes
Education
Academic performance
- • Grade improvements
- • Test score changes
- • Enrollment trends
- • Learning progress
Calculation Tips & Common Mistakes
Best Practices
- ✓Always use the original value as the denominator
- ✓Use absolute value of original to handle negatives
- ✓Be consistent with units and time periods
- ✓Round final results, not intermediate values
- ✓Consider context when interpreting results
Common Mistakes
- ✗Using new value as denominator instead of original
- ✗Forgetting absolute value with negative originals
- ✗Confusing percentage change with percentage points
- ✗Not accounting for compounding in sequential changes
- ✗Mixing different time periods or units
Advanced Concepts
Sequential Percentage Changes
When multiple percentage changes occur sequentially, you cannot simply add the percentages. Each change builds on the previous result.
Example:
Price increases 20%, then decreases 10%
Final change = (1.20 × 0.90) - 1 = 8% increase
NOT 20% - 10% = 10%
Reverse Percentage Calculation
To find the original value before a percentage change, divide the new value by (1 + percentage change as decimal).
Formula:
Original = New ÷ (1 + Percentage Change)
Example: After 25% increase, price is $125
Original = $125 ÷ 1.25 = $100