# CPI Inflation Calculator – Consumer Price Index

URL: https://speedycalculator.com/calculators/finance/cpi-inflation/
Last updated: 2026-10-25

> The CPI inflation calculator works out the inflation rate between any two years from 1913 to today using U.S. CPI-U annual averages – or from two CPI values you enter – and adjusts an amount for inflation.

## Inputs

- Use
- Start year
- End year
- Starting CPI
- Ending CPI
- Years between (for your CPI values)
- Amount

## Results

- Starting CPI used
- Ending CPI used
- Inflation rate
- Inflation-adjusted amount
- Average annual inflation

## Formula

```
Inflation rate = (CPI end − CPI start) ÷ CPI start × 100
Adjusted amount = amount × CPI end ÷ CPI start
Average annual rate = (CPI end ÷ CPI start)^(1/years) − 1
```

## Explanation

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

FieldWhat to enterUseChoose one: U.S. CPI by year, My own CPI valuesStart yearChoose one: 2026 (estimate), 2025, 2024, 2023 …End yearChoose one: 2026 (estimate), 2025, 2024, 2023 …Starting CPIA numberEnding CPIA numberYears between (for your CPI values)A numberAmountAmount 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 CPIInflation rate (%)129.424.38194.124.38258.824.38323.524.38388.224.38517.624.38

## Worked 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 %.

## FAQ

**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.


## Sources

- [U.S. Bureau of Labor Statistics – Consumer Price Index](https://www.bls.gov/cpi/)
- [Federal Reserve Bank of Minneapolis – CPI 1913–](https://www.minneapolisfed.org/about-us/monetary-policy/inflation-calculator/consumer-price-index-1913-)