CPI Inflation Calculator
Convert the purchasing power of U.S. dollars between two dates using the Consumer Price Index for All Urban Consumers (CPI-U), all items, U.S. city average.
Equivalent amount
$40,882.70
in March 1991 dollars using CPI ratios.
CPI-U expresses the price level relative to its base comparison period (1982–84 = 100). To translate nominal dollars dated at Period A into Period B nominal dollars holding the CPI basket assumption:
Equivalent_B = Amount_A × CPI_B ÷ CPI_A
This is the same structure used for “has the same buying power as” calculators that compare two calendar months. It is not a tax, wage, or rent estimate; it is a general price index translation.
Sources and methodology mirrors the public CPI-U series published by the U.S. Bureau of Labor Statistics. See the supplemental historical CPI-U worksheet for index values referenced here: CPI data tables (BLS)
CPI-U tracks the price level of a broad basket of urban consumer goods and services. Comparing two index values approximates how many dollars were required in one month versus another if you hold the aggregate basket concept constant.
If you swap the start period and target period, you invert the CPI ratio and change the storyline (for example, translate past dollars forward or deflate present dollars backward).
CPI-U is a national U.S. composite and may not mirror your hometown or your household spending mix.
Tax brackets, rents with caps, insurance plans, contractual COLA wording, academic research, and pensions often reference different CPI flavors or smoothing rules. Confirm any legal or contractual text independently.