Trillions, Billions & Millions

Few of us have any idea how much a trillion is—or a billion—or even a million—because nothing in our personal experience is measured in numbers that large. It's difficult to visualize meaningful examples, but I'll try.

Please note that the following applies to American usage of these terms.
They are used differently in some other parts of the world.

First, comparisons between the three quantities:

  • A million is a thousand times as large as a thousand.
  • A billion is a thousand times as large as a million.
  • A trillion is a thousand times as large as a billion.


  • A thousand inches = nearly 28 yards.
  • A million inches = about 16 miles.
  • A billion inches = about 16,000 miles.
  • A trillion inches = about 16 million miles.
  • A thousand seconds = nearly 17 minutes.
  • A million seconds = nearly 12 days.
  • A billion seconds = nearly 32 years.
  • A trillion seconds = nearly 32,000 years.
    (32,000 years ago is long before the beginning of writing or any known civilization, likely before language, about the time of the first cave paintings and crude sculptures, perhaps almost back to the inception of war!)

A dollar bill is a little thicker than a typical human hair.

  • A stack of a thousand one-dollar bills is more than 4 inches high.
  • A million would be about as high as a 40-story building.
  • A billion would be nearly 68 miles high.
  • A trillion would be nearly 68,000 miles high.
  • If you earn $50,000 per year, it would take you 20 years to earn a million dollars.
  • It would take you 20,000 years to earn a billion dollars.
  • It would take you 20 million years to earn a trillion dollars.

Then what would a trillion dollars buy? (figures approximate for 2012)

  • 143,000 brand new elementary schools—one for every 245 students—more than twice as many as we have now
  • 570,000 wind turbine generators—we have fewer than 50,000 now
  • 3.7 million new homes (@ $273,000 each)—that would be six homes for every homeless person in America
  • 32 million new cars (@ $31,000 each)—that would be one for every four households in America, or one for every six drivers
  • Please note: no one is suggesting buying six homes for a homeless person or tripling our elementary schools—these examples are meant to help us understand the magnitude of a trillion dollars.

Next time you see a headline about a $17 trillion debt, or a $700 billion financial package, think about it in terms of these examples. Perhaps it will mean more.

How about larger numbers?
The next named number in American usage is a quadrillion (a thousand times as large as a trillion). The word is seldom heard, because few disciplines deal with such large quantities. Applications in science and mathematics regularly employ quantities of unimaginably greater magnitude, but usually don't name them. They are expressed in an exponential format, called scientific notation.