Calculate inflation between two CPI readings.
Please do not make financial decisions based on these results.
What is the CPI Inflation Calculator – Consumer Price Index?
Calculate inflation between two CPI readings. To use the CPI Inflation Calculator – Consumer Price Index, enter earlier cpi, latest cpi, amount to adjust; it returns inflation between readings, amount in later dollars, and shows them instantly as you type.
Reading the economy with formulas
Output first: use the GDP calculator for the expenditure approach and the Real GDP Calculator to remove inflation. Prices next: the CPI inflation calculator and Real Interest Rate Calculator show the true return on money.
For policy, the Taylor Rule Calculator suggests a rate from inflation and the output gap, and the Spending Multiplier Calculator shows how a change in spending ripples through GDP.
- Labor. Unemployment, participation, the natural rate and Okun’s law describe the job market.
- Money. Money multiplier, reserve ratio, money supply and velocity explain monetary conditions.
- Trade and currency. PPP, interest rate parity, cross rates and carry trades link currencies and prices.
How to use the CPI Inflation Calculator – Consumer Price Index
- Enter your numbers. The inputs are Earlier CPI, Latest CPI, Amount to adjust ($). Use real figures from your own records where you can. Fields marked optional can stay at zero.
- Read the result. The highlighted box gives the Inflation between readings, and the cards below show Amount in later dollars. Tables and charts break it down further.
- Test other scenarios. Results update as you type. Change one value at a time to see what drives the answer, and press Reset to go back to the defaults.
Formula and how it works
Example with real numbers
Here is the CPI Inflation Calculator – Consumer Price Index using the default values shown in the calculator above:
Inputs
| Earlier CPI | 318.5 |
|---|---|
| Latest CPI | 334.98 |
| Amount to adjust ($) | 100 |
Results
| Inflation between readings | 5.17% |
|---|---|
| Amount in later dollars | $105.17 |
With these inputs the calculator returns Inflation between readings: 5.17%. Change any value in the calculator to see how the result moves.
What if you change one input?
Sensitivity check: raising Earlier CPI from 318.5 to 382 (about 20% higher) and leaving everything else as in the example above changes the results like this:
| Result | Example | After the change | Change |
|---|---|---|---|
| Inflation between readings | 5.17% | -12.31% | -337.9% |
| Amount in later dollars | $105.17 | $87.69 | -16.6% |
The input that moves the result most is the one to check twice. Change it in the calculator above to test your own case.
What the results tell you
The results panel of the CPI Inflation Calculator – Consumer Price Index reports Inflation between readings and amount in later dollars. Compare these figures while changing one input at a time, and use the related calculators below to look at the same situation from another angle.
Method and limits. This calculator applies the formula in the section above to your inputs, in your browser; nothing you enter is stored on our servers. The result is only as accurate as the numbers you enter and the formula shown above. It is for information, not financial, tax or legal advice.
Frequently asked questions
Which CPI does the BLS publish?
CPI-U (all urban consumers) is the most quoted headline index.
What is the spending multiplier?
It is 1 divided by one minus the marginal propensity to consume, so an MPC of 0.8 gives a multiplier of 5.
Where do the economic inputs come from?
Use official sources such as the BEA, BLS, Federal Reserve, IMF or World Bank for GDP, CPI, unemployment and money supply figures.
Are the results guaranteed?
No. Results depend entirely on the numbers you enter and the formulas shown on this page. Please do not make financial decisions based on them alone; confirm important figures with a licensed professional.
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