Variables
Description
What is this formula?
The Purchasing Power Index measures the relative purchasing power of money based on a price index.
As prices increase, purchasing power decreases. The index provides a simple way to quantify how much purchasing power remains relative to a base period.
When to use it
Use this formula when comparing purchasing power across different periods, evaluating inflation effects, or converting economic values into real terms.
Example
Consumer Price Index:
CPI = 125
Formula:
PPI = 100 / CPI
Substitution:
PPI = 100 / 125
PPI = 0.80
Result:
Purchasing power is 80% of the purchasing power in the base period.
Applications
- Inflation analysis
- Cost of living studies
- Real income evaluation
- Economic education
- Historical price comparisons
Note
This index is a simplified representation of purchasing power based on a selected price index. Results depend on the quality and scope of the CPI used. Different countries and institutions may calculate consumer price indexes using different baskets of goods and services.