The Consumer Price Index (CPI) ... The formula for doing so looks like this: CPI = Cost of market basket in a given year/Cost of market basket in base year x 100.

The formula below will help us calculate what November 2015 dollars are worth in terms of January 1990 dollars: In other words, we know that $100 in Nov. 2015 would buy as many goods and services ...

From December 1982 through December 2011, the CPI-E rose at an annual average rate of 3.1 percent, compared with increases of 2.9 percent for both the CPI-U and the CPI-W.

If the CPI increases, purchasing power declines, as more currency is needed to buy the same items. For example, if a basket of goods cost $1,000 in the base year and $1,100 today, the CPI would be ...

This equation helps determine how inflation impacts the real value of money. If the CPI increases, purchasing power declines, as more currency is needed to buy the same items. Story Continues ...

The most widely used measure of inflation in the U.S. is the Consumer Price Index for All Urban Consumers, or CPI-U, which is put out by the U.S. Bureau of Labor Statistics (BLS).