If you’ve ever wondered about the relative worth of something over time, the present value of a past amount of money, or what a historic price in British pounds is worth in US dollars today, you should check out the Measuring Worth website:
We are concerned with measuring the worth of items with which both a monetary value and a past time period are clearly associated. Examples are: A loaf of bread sold for seven pennies in 1915; what is its “value” today? Your great-grandfather’s estate was $1000 or £200 in 1900; what is that worth today?
Created by economists, the site contains historical data sets and calculators to help measure things like comparative relative values (of the US dollar from 1774 to the present, the UK pound from 1830 to the present, the Chinese Yuan from 1952 to 2007, and the Japanese Yen from 1879 to 2007), comparative growth rates of economic variables, historical inflation rates, growth rates of daily stock indexes, etc.
Comparing the value or worth of something over time is very complicated (the site has six different ways to calculate the relative value of a US dollar amount), so there’s an essay, a user guide, and other detailed information to help you figure out which calculator to use and interpret the results.