CPI Inflation Calculator — Purchasing Power by Year
Enter an amount and the Consumer Price Index (CPI) values for any two years to calculate the inflation-adjusted equivalent, cumulative inflation, and how much purchasing power was retained or eroded. CPI values are published by national statistics offices — US values from the BLS, EU from Eurostat.
What the start-year amount is worth in end-year money
- 1
CPI ratio (end ÷ start)
135 ÷ 100 = 1.35Prices at the end year relative to the start year. - 2
Inflation-adjusted amount
1,000 × 1.35 = 1,350
How does this calculator work?
Adjust money between years with: Adjusted amount = Original × (CPI end ÷ CPI start). Cumulative inflation = (CPI end − CPI start) ÷ CPI start × 100. Enter the CPI index values from your national statistics office (e.g. US BLS, Eurostat) for the two years to get the inflation-adjusted equivalent and annual average inflation rate.
Formula
How this is calculated
The Consumer Price Index (CPI) is a basket-of-goods index that tracks the average price level of goods and services bought by households. Published monthly by national statistics agencies, it is the standard benchmark for measuring inflation and adjusting monetary amounts across time. A CPI of 135 vs a base of 100 means prices have risen 35% since the base year.
To convert a monetary amount between two years, multiply by the ratio of the end-year CPI to the start-year CPI. This tells you what the original amount is worth in end-year money — how much you would need in the later year to buy the same goods. The inverse ratio gives the real purchasing power of the original sum expressed in end-year terms. The cumulative inflation percentage is simply the CPI change as a fraction of the start CPI, and the compound annual rate is back-calculated from that total change.
CPI values in this calculator are pre-filled as editable illustrative estimates (base year 2010 = 100, end year 2024 = 135, implying ~35% cumulative inflation). Replace them with the actual published index values for your country and the specific CPI series you want (headline CPI, core CPI, HICP in the EU, etc.). The US BLS publishes monthly series at bls.gov/cpi; Eurostat publishes HICP data at ec.europa.eu/eurostat.
Frequently asked questions
National statistics offices publish CPI data freely: BLS (bls.gov/cpi) for the US, ONS (ons.gov.uk) for the UK, Eurostat for the EU, RBI for India, and ABS (abs.gov.au) for Australia. Use the same series consistently — mixing headline and core CPI between years gives incorrect results. Annual average values are more stable than monthly figures for long-term comparisons.
Headline CPI includes all items, including volatile food and energy prices. Core CPI strips out food and energy to show underlying inflation trends. For long-run purchasing power comparisons, headline CPI is usually more appropriate because it reflects what households actually pay. Central banks often target core CPI for monetary policy because food and energy volatility would create unnecessary policy swings.
CPI measures average price changes for a representative household basket. Individual experience depends on your personal spending pattern — if you spend heavily on housing in a city with rapid rent rises, your personal inflation rate is much higher than CPI. If you spend mainly on electronics (prices fall over time) your inflation rate is lower. CPI is the standard economic convention, but your actual purchasing power change may be quite different.
TG we-Calculate Editorial Team. (2026). CPI Inflation Calculator — Purchasing Power by Year [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/cpi-inflation-calculator
TG we-Calculate Editorial Team. "CPI Inflation Calculator — Purchasing Power by Year." TG we-Calculate. 2026. https://we-calculate.com/calculator/cpi-inflation-calculator.
TG we-Calculate Editorial Team, "CPI Inflation Calculator — Purchasing Power by Year," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/cpi-inflation-calculator
@misc{wecalculate_cpi_inflation_calculator, title = {CPI Inflation Calculator — Purchasing Power by Year}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/cpi-inflation-calculator}}, year = {2026}, note = {TG we-Calculate} }
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