CPI = Consumer Price Index
Find the current CPI from the official statistics agency in your country
Use the same base year for both time periods
Get the CPI for the earlier period
Get the CPI for the later period
Use the formula: CPI = (Cost of market basket in current year / Cost of market basket in base year) × 100
If comparing price changes, use: Inflation rate = [(CPI in later period – CPI in earlier period) / CPI in earlier period] × 100
If converting money values, use: Adjusted value = Original value × (CPI in later period / CPI in earlier period)