The CPI tracks prices of a fixed basket of consumer goods and services. Inflation averaged about 3% a year since 1913, but with big swings: over 13% in 1980 and below zero in 2009 and the 1930s.
How to use the CPI Inflation Calculator – Consumer Price Index
- Use
- Start year
- End year
- Starting CPI
- Ending CPI
- Years between (for your CPI values)
- Amount
Results update as you type, and every field accepts the units shown in its menu.
How it works
Choose the start and end years – or enter your own CPI values – and an amount to adjust.
Tips
- Use real (inflation-adjusted) figures to compare across years.
- Check whether data are seasonally adjusted.
- Use the same currency and base year throughout.
- Economic models simplify reality – treat results as illustrations, not forecasts.
Common mistakes to avoid
- Mixing nominal and real values.
- Comparing percentage changes with percentage-point changes.
- Treating correlations as causes.
Inputs explained
| Field | What to enter |
|---|---|
| Use | Choose one: U.S. CPI by year, My own CPI values |
| Start year | Choose one: 2026 (estimate), 2025, 2024, 2023 … |
| End year | Choose one: 2026 (estimate), 2025, 2024, 2023 … |
| Starting CPI | A number |
| Ending CPI | A number |
| Years between (for your CPI values) | A number |
| Amount | Amount in your currency |
What each result means
- Inflation rate = ([Ending CPI used]÷[Starting CPI used] – 1)×100
- Inflation-adjusted amount = [Amount]×[Ending CPI used]÷[Starting CPI used]
Example values
How the main result changes when Starting CPI changes and everything else stays at the example values above:
| Starting CPI | Inflation rate (%) |
|---|---|
| 129.4 | 24.38 |
| 194.1 | 24.38 |
| 258.8 | 24.38 |
| 323.5 | 24.38 |
| 388.2 | 24.38 |
| 517.6 | 24.38 |
Formula
Inflation rate = (CPI end − CPI start) ÷ CPI start × 100Adjusted amount = amount × CPI end ÷ CPI startAverage annual rate = (CPI end ÷ CPI start)^(1/years) − 1Worked example
Inputs — Use: U.S. CPI by year; Start year: 2020; End year: 2025; Starting CPI: 258.8; Ending CPI: 321.9; Years between (for your CPI values): 5; Amount: $1,000.
Results — Starting CPI used = 258.8; Ending CPI used = 321.9; Inflation rate = 24.38 %; Inflation-adjusted amount = $1,243.82; Average annual inflation = 4.46 %.
Frequently asked questions
How is CPI inflation calculated?
(CPI end − CPI start) ÷ CPI start × 100.
What was inflation from 2020 to 2025?
About 24% cumulative (CPI-U 258.8 → 321.9).
Where does CPI data come from?
The U.S. Bureau of Labor Statistics.
What formula does the CPI Inflation Calculator – Consumer Price Index use?
Inflation rate = (CPI end − CPI start) ÷ CPI start × 100.