Would you be middle class in Oslo? Bangkok? Mumbai?

The hard way to figure that out would be to look at how much local currency your dollars would buy, then figure out how far that currency would stretch to cover rent, food and other essentials.

The easy way: the Big Mac Index, or at least a version of it.

The Big Mac Index, created by The Economist, has long been used as a way to illustrate the shifts in purchasing power of different currencies. A McDonald's Big Mac sandwich that costs $3.54 in New York, for example, costs 1,550 pesos in Chile.

* Bing: Find more on the cost of living anywhere

Investment bank UBS takes the concept further, translating each currency into units of work. Thus a Big Mac that takes 14 minutes to earn in New York takes nearly an hour in Budapest. (The hourly wage used for New York was $19, though of course that shifts constantly with exchange rates.)

The 2009 version of the UBS survey (.pdf file) adds another good with near-universal familiarity: The iPod. A worker in Zurich or New York labors just nine hours to buy an 8gb iPod Nano; the same purchase takes a month of nine-hour days in Mumbai.

More on saving and debt:

More on saving and debt:

Five impulse buys that drain your cash
Don't miss back-to-school tax savings
Staying fit -- physically & financially
What a pet really costs
The great recession is over -- or is it?
Blog:Smokers grow their own tobacco

Of course, UBS isn't all fast food and hip-hop. The survey measures the relative costs of 122 goods and services, plus rent. New York, Oslo, Geneva and Tokyo are the most expensive places to live, with rent factored in. The cheapest? Kuala Lumpur, Malaysia; Manila, Philippines; and Delhi and Mumbai in India.

The cost of living figures in the chart below are based off New York prices; if the cost-of-living column for Taipei, Taiwan, reads 48.3, for example, the cost of living is 48.3% of that in New York.

* Related:Hardest working countries

Also worth noting is UBS' measurement of the number of hours worked each year: Workers in Cairo and Seoul, South Korea, worked 50% more hours than those in Paris.

How long you have to work to buy . . .

How long you have to work to buy . . .