4. Subtract CPI 1 from CPI 2. This will give you the percentage change in price since you purchased the original product. If it is a positive number, you are experiencing inflation. If the number is negative, then you are experiencing deflation:
4. Subtract CPI 1 from CPI 2. This will give you the percentagechange in price since you purchased the original product. If it is a positive number, you are experiencing inflation. If the number is negative, then you are experiencing deflation: