This calculator uses the Consumer Price Index (1982-84=100) and the following simple formula to convert dollar amounts between two different years.

Converted$=(StartYear$/StartYearCPI)*ConvertYearCPI
Any time you compare dollar amounts over time, the amounts should be adjusted for price inflation. With this calculator, you can compare the real buying power of any dollar amount you enter in the box. For example, $100 in 1913 had the same buying power as $1,584.85 in 1996.

The conversion factor calculation is simply the ratio of the two CPI figures.
Conversion Factor = ConvertYearCPI/StartYearCPI

The calculator program uses annual data. These annual data are the averages of the monthly CPI figures. This means that data for the latest year are incomplete. The CPI figure used for the last year is the average of all data available for that year. As the year progresses, and more data become available the calculator gets updated. If you have questions about the CPI, visit the CPI homepage where you will find a wealth of information on this statistic.

Source: Bureau of Labor Statistics.