McDonald's Big Mac cost $2.63, measured in PPP, at the end of 2012 SHUTTERSTOCK

Adjusted for currency exchange rates at the end of 2012, McDonald's popular Big Mac sandwich cost $2.63 in Poland, making it 39.2% cheaper than its counterpart in the United States. By this measure, the złoty is still rather strongly undervalued.

The figures come from the most recent edition of the Big Mac Index, published by The Economist.

Calculated using the index's methodology, the US dollar should cost zł.2.08, not zł.3.07 as it does today. Since the Polish currency tumbled dramatically in 2009, Polish products have remained unnaturally cheap in comparison with other countries.

Only in 15 out of 45 countries analyzed is the burger cheaper than in Poland. Norway, Sweden and Venezuela came on top of the list, while India and South Africa were tailing behind with Big Macs over 50% cheaper than in the US.

The index is a tongue-in-cheek exchange-rate indicator of whether or not currencies are at their “correct” level. It is based on the theory of purchasing-power parity, which posits that in the long run exchange rates should converge to a level that would make the prices of a universal basket of goods and services (in this case, the burger) identical all over the world. The authors of the index chose the Big Mac sandwich because of its widespread availability.

Marta Mardosz