The Economist has been publishing the Big Mac Index since 1986 as an informal way to calculate the values of currencies around the world against the US dollar using the theory of purchasing power parity—as they explain, "the notion that in the long run exchange rates should move towards the rate that would equalise the prices of an identical basket of goods and services (in this case, a burger) in any two countries."
The Big Mac Index isn't meant to be a serious currency-comparison tool, but if you're interested in comparing Big Mac prices around the world and how much those prices undervalue or overvalue a country's currency against another, check out The Economist's nifty interactive Big Mac Index, which was updated last week.
For a quick explanation of the Big Mac index, check out the animated video below.
About the author: Robyn Lee is the editor of A Hamburger Today and takes many of the photos for Serious Eats. She'll also doodle cute stuff when necessary. Read more from Robyn at her personal food blog, The Girl Who Ate Everything.