Percentage Change
Relative increase or decrease.
What does Percentage Change mean?
Percentage change measures how much a value has increased or decreased relative to its original amount. It is one of the most commonly used metrics in everyday life — from tracking stock price movements and salary raises to comparing test scores and population growth. A positive percentage means an increase; a negative percentage means a decrease.
How to calculate Percentage Change
The formula is: Percentage Change = ((New Value − Old Value) / |Old Value|) × 100. For example, if a product's price goes from $80 to $100, the change is ((100 − 80) / 80) × 100 = 25% increase. If it drops from $100 to $80, the change is ((80 − 100) / 100) × 100 = −20% decrease. Note that a 25% increase followed by a 20% decrease returns to the original value — percentage changes are not symmetric.
FAQ
Because the base value changes. Going from 100 to 125 is a 25% increase (base 100), but going from 125 back to 100 is only a 20% decrease (base 125). The denominator is different in each direction, which is why the percentages differ.
Percentage change is undefined when the old value is zero, because you would be dividing by zero. In such cases, you can only describe the change in absolute terms, not as a percentage.
Percentage change is the relative difference between two values. Percentage points describe the absolute difference between two percentages. For example, if an interest rate goes from 5% to 7%, that is a 2 percentage point increase but a 40% percentage change.
Yes. A percentage change greater than 100% means the value more than doubled. For example, going from 50 to 150 is a 200% increase. There is no upper limit to percentage increases, though decreases are capped at −100% (the value drops to zero).
Multiply the old value by (1 + percentage / 100). For example, a 30% increase on $200: 200 × 1.30 = $260. For a 15% decrease on $200: 200 × 0.85 = $170.
Related calculators
- Compound Interest— Growth of money with reinvested interest.
- CAGR— Average annual growth rate.
- ROI— Return relative to investment cost.
- Exponential Growth— Growth proportional to size.