Use the orange knobs to choose a dollar amount at a year in the past. (For example, roundtrip flights between New York and L.A. cost $310 in 1974. Gasoline cost 20 cents per gallon in 1930.)
See how the dollar cost has changed over time.
"Spending $10 in 1970 is like spending $60 in 2013."
The calculator itself does not contain any product-specific data, but it is useful for comparing the real prices of products over time. For example, consumers in 1930 paid 20¢ for a gallon of gas, which the inflation calculator shows is equivalent to $2.36 in 2004. It turns out that the true price of gas in 2004 was $1.85. This implies that the real price of gas went down relative to other consumer products (since $1.85 is less than $2.36).
Note that as the dollar cost goes up (due to inflation), the buying power of a dollar goes down (because you need more dollars to purchase the same set of goods).
If you'd like this calculator to support inflation data for other countries, let us know.