Percentage Change Calculator
Calculate percentage increase or decrease between two values with clear step-by-step explanation.
About Percentage Change Calculator
A percentage change calculator determines the percentage increase or decrease between two values, along with the absolute change. This is different from a simple percentage calculation — percentage change specifically measures how much a value has grown or shrunk relative to its starting point. It is widely used in finance (stock returns, inflation), economics (GDP growth), retail (price changes), and science (experimental results).
How to Use
Enter the original (old) value and the new value. The calculator instantly shows the percentage change (positive for increase, negative for decrease), the absolute change (the numerical difference), and a clear explanation of whether the value increased or decreased and by how much.
Formula / Key Equations
Percentage Change = ((New Value - Old Value) / Old Value) × 100. Absolute Change = New Value - Old Value. Positive result = increase. Negative result = decrease. Note: the denominator is always the original (old) value, not the average of both values.
Common Use Cases
Tracking stock market gains and losses. Calculating year-over-year revenue growth for businesses. Measuring inflation or deflation rates. Analyzing price changes before and after sales. Comparing test scores between semesters. Evaluating changes in website traffic or conversion rates. Scientific experiments measuring before/after treatment effects.
Limitations
Percentage change can be misleading with very small original values — a change from 1 to 3 is a 200% increase, which sounds dramatic but represents a small absolute change. It cannot be calculated when the original value is zero (division by zero). For changes spanning multiple periods, use compound annual growth rate (CAGR) instead of simple percentage change.
Frequently Asked Questions
What is the difference between percentage change and percentage difference?
Percentage change measures growth from an old value to a new value using the old value as the base. Percentage difference measures the relative difference between two values using their average as the base, without designating either as old or new. Use percentage change for time-series data and percentage difference for comparing two items.
How do I calculate percentage change when the original value is negative?
The formula still works: ((new - old) / old) × 100. For example, going from -10 to -5 is a 50% decrease (becoming less negative). Going from -10 to 5 is a 150% increase. Be cautious interpreting percentage changes with negative bases, as results can be counterintuitive.
Why can't I calculate percentage change from zero?
Division by zero is mathematically undefined. If your original value is zero, any change (no matter how small) would require dividing by zero. In such cases, it is better to report the absolute change or use a different metric.
What is a good percentage change for business revenue?
Context matters — a 5% annual revenue growth is solid for a large, established company, while a 100%+ growth rate is expected for an early-stage startup. Compare your growth rate to industry benchmarks and historical performance rather than using a universal threshold.
How do I calculate compound growth over multiple periods?
For multi-period growth, use CAGR (Compound Annual Growth Rate): CAGR = (Ending Value / Beginning Value)^(1/n) - 1, where n is the number of periods. This gives the equivalent constant annual growth rate. Simple percentage change does not account for compounding.
Related Tools
Scientific Calculator
Full-featured scientific calculator with trigonome...
Fraction Calculator
Add, subtract, multiply, and divide fractions. Sim...
Square Root Calculator
Calculate square roots, cube roots, and nth roots ...
Standard Deviation Calculator
Calculate mean, median, mode, standard deviation, ...
Probability Calculator
Calculate probabilities for single and multiple ev...
Exponent Calculator
Calculate powers and exponents. Supports fractiona...