Calculators ·
How to Calculate Percentage Increase and Decrease
Understand the percentage change formula with simple examples for prices, measurements and business figures.
The basic formula
Percentage change is calculated by taking the difference between the new value and the original value, dividing by the original value, and multiplying by 100.
Example of an increase
If a price changes from 100 to 120, the difference is 20. Dividing 20 by the original 100 gives 0.20, or a 20% increase.
Example of a decrease
If a value changes from 200 to 150, the difference is -50. Relative to the original 200, that is a 25% decrease.
Why the original value matters
The percentage is measured against the starting value. Using the new value as the denominator can produce a different and misleading result when describing a change.