When we think of what it means to be "upper class," images of luxury cars, stately mansions and all the other ostentatious trappings of the aristocracy might come to mind.

But demographers and researchers have to actually attach real-world numbers to such terms, and by one measure, millions of far more humble Americans can count themselves among the upper class, and they probably don't even realize it. 

For its purposes, the Pew Research Center considers a household to be upper class if its income is double the U.S. median household income.

This means that, on average, a single person living alone needs to make just $78,281 to be considered upper class. For a household of four, the minimum combined income to make the cut is $156,561.

By that measure, a number of entire work sectors likely qualify as upper class: most software engineers, attorneys and physicians in the U.S. are easily clearing that bar, for example. 

Of course, your money only goes so far depending on where you live. Making $80,000 a year might be a small fortune in Wichita, but it's not going to afford you the same lifestyle in San Francisco. 

Pew came up with a nifty calculator that allows you to figure out what class you're statistically a member of based on where you live. Turns out you're going to need to make $98,000 to be considered upper class in the Bay Area (It's $71,000 in Wichita).

Pew's measure is still relatively arbitrary, but it does provide a handy tool to see how you stack up.

In case you were wondering, Pew's latest numbers show that the upper class actually shrank by a percentage point over the past half-decade, ceding that ground back to the 52 percent counted among the middle class. Over the past 45 years, the middle class shrank by almost ten percent while the upper class has grown by a slightly larger amount than the also-expanding lower class.

Of course, life in each class tier can look vastly different depending on how you manage your money. This particular Pew measure doesn't take total assets into account, after all. You could be taking a year off to live large off your previous successes and be considered low income, I suppose. 

Then again, if you've really managed your affairs well, those assets should be generating a nice enough income to register you in the upper class this year as well.