English: The Big Mac index was introduced in The Economist in 1986 as a semi-humorous illustration of PPP and has been published by that paper annually since then. The index also gave rise to the term "burgernomics".

Burgernomics was never intended as a precise gauge of currency misalignment, merely a tool to make exchange-rate theory more digestible. Yet the Big Mac index has become a global standard, included in several economic textbooks and the subject of dozens of academic studies.

One of the methods of predicting exchange rate movements is that the rate between two currencies should naturally adjust so that a sample basket of goods and services should cost the same in both currencies.

In the Big Mac Index, the basket in question is a single Big Mac burger as sold by the McDonald's fast food restaurant chain. The Big Mac was chosen because it is available to a common specification in many countries around the world as local McDonald's franchisees at least in theory have significant responsibility for negotiating input prices. For these reasons, the index enables a comparison between many countries' currencies.