How to Calculate Percentage Change
Percentage change measures how much a value has grown or shrunk relative to its original amount. It's used for price changes, salary increases, sales growth, and many other everyday comparisons.
Step-by-step
- 1
Identify the old and new values
Note the starting value and the final value you want to compare.
- 2
Find the difference
Subtract the old value from the new value.
- 3
Divide by the old value
Divide the difference by the original (old) value.
- 4
Multiply by 100
Convert the result to a percentage by multiplying by 100.
The percentage change formula
Percentage change = ((New value − Old value) ÷ Old value) × 100. A positive result is an increase; a negative result is a decrease.
Worked example
A product rises from $100 to $120. The difference is $20, divided by the old value ($100) gives 0.20, and multiplied by 100 gives a 20% increase. If it dropped from $100 to $80, the result would be −20%, a 20% decrease.
Percentage change vs. percentage points
These are different. If an interest rate rises from 5% to 7%, that is a 2 percentage point increase — but a 40% relative increase, because 2 ÷ 5 × 100 = 40%.
Frequently Asked Questions
How do I calculate percentage increase?
Subtract the old value from the new value, divide by the old value, and multiply by 100.
What does a negative percentage change mean?
A negative result means the value decreased rather than increased.
What's the difference between percentage change and percentage points?
Percentage points are the arithmetic difference between two percentages, while percentage change is the relative difference expressed as a percent.