A trillion dollars used to be an almost unimaginable sum. For most people, it still is, but we’re seeing that figure more often in reports about the federal budget deficit, the cost of the bank bailout and so on.

James Hamilton at Econbrowser offers a handy way to think about that giant number:

A trillion dollars is about the total amount collected in income taxes by the U.S. federal government in fiscal year 2006 — $1.04 trillion, if you’re curious to use the exact number. That gives me a simple rule of thumb for personalizing these numbers. If I want to know what an additional trillion dollars in government borrowing or spending will mean for me, I just imagine what it would be like to pay twice as much in federal income taxes for one year.

 There are other ways to raise a trillion dollars, Hamilton says after noting the projected deficits of $1.75 trillion in 2009 and $1.17 trillion in 2010. But they’re not very pleasant, either:

Or maybe the Federal Reserve could help out some. The total currency in circulation at the moment is about $900 billion. If the Fed were to create as much money in the next year as it did in total over all the preceding 95 years combined and use it to buy up some of the outstanding Treasury debt, it would doubtless produce an inflation rate in excess of 100%, but at least it would get us most of the way through another of those trillion.

 Just for fun, I looked up figures on the Post-Dispatch’s use of the word “trillion.” It appeared in 337 stories last year, up from 266 in 1998. In the first two months of this year, the T-word already has made 95 appearances. If we continue talking trillions at that rate for the rest of 2009, that would come to 570 mentions, a 69 percent jump over last year.