Inflation Calculator
Free to use, with no sign up. Compare the purchasing power of US dollars using published consumer prices.
Loading the latest BLS CPI-U data…
Result
Equivalent value = amount × CPI_end / CPI_start. Cumulative inflation = 100 × (CPI_end / CPI_start − 1). Average annual rate = 100 × [(CPI_end / CPI_start)^(1 / years) − 1], where years is the signed month difference / 12, or the year difference for annual averages.
The average annual rate describes the forward historical trend even when converting backward. For the same period the annual rate is not applicable. All intermediate arithmetic uses unrounded CPI ratios; dollar results round to cents. The table compares the starting month each year (or annual averages), followed by your exact ending period.
Worked example: $100 in January 2000 (CPI 168.8) equals $152.83 in January 2020 (CPI 257.971). Cumulative inflation is 52.8264%; the average annual rate over 20 years is 2.1433%.
| Period | CPI-U | Equivalent USD |
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Source: BLS CPI-U all-items flat file, series CUUR0000SA0, US city average, not seasonally adjusted (1982–84 = 100). Bureau of Labor Statistics Consumer Price Index. BLS data is a US government work in the public domain. Fetch date appears when the data loads. The feed checks daily; annual averages are available only for complete published years. BLS marks October 2025 unavailable; this tool does not interpolate it.
Arithmetic on published CPI, not financial advice. CPI measures an average consumer basket; personal expenses, regional prices, investment returns and future inflation can differ.
Related calculators: Compound Interest Calculator and Investment Calculator.
How to use this tool
Enter an amount in USD and choose a starting and ending month and year. Select Annual average for both months to compare full years using BLS annual averages. Select Calculate to see equivalent dollars, cumulative inflation and the average annual rate. You can also choose an earlier ending date to convert backward.
Frequently asked questions
Which inflation data does this calculator use?
US Bureau of Labor Statistics CPI-U, all items, US city average, not seasonally adjusted: series CUUR0000SA0. Monthly observations begin in January 1913. Annual mode uses the published M13 annual averages, not December values.
Can I calculate inflation backward or compare annual averages?
Yes. Choose an earlier ending period for backward conversion, or Annual average for both dates. The cumulative percentage follows your chosen direction; the average annual rate describes the forward historical trend over the span. The same period has no annualized rate.
Is it free, and are my inputs private?
Yes. Only the public CPI data file is fetched. Your entries and arithmetic stay in your browser with no sign up or browser storage. CPI describes an average basket, not your personal expenses or future prices.
What happens if a CPI month is unavailable?
The calculator refuses unavailable endpoints and labels missing intermediate table rows. BLS marks October 2025 unavailable. No values are estimated. A failed feed refresh keeps the last validated data; check the latest month and fetch date shown on the page.