How Much Is A “Billion”?

By Simon Kewin

In the recent economic troubles, we’ve grown used to hearing about millions, billions and even trillions of dollars, pounds, euros etc. It’s worth noting, however, that these words do not have a universally-agreed meaning. What one person means by billion can be very, very different from that assumed by another.

A thousand is always 1,000 and a million is always 1,000,000. After that things become less clear.

In the USA, the name given to 1,000,000,000 is a billion. However, in Britain and other places, this figure is sometimes referred to as “one thousand million” with a billion being 1000 times more : 1,000,000,000,000. The following table lists the meanings of the various words in the “American” and traditional “British” systems :

1,000,000,000
“American” 1 billion
“British” 1 thousand million

1,000,000,000,000
“American” 1 trillion
“British” 1 billion

1,000,000,000,000,000
“American: 1 quadrillion
“British 1 thousand billion

1,000,000,000,000,000,000
“American” 1 quintillion
“British” 1 trillion

And so forth. In fact, the “American” and “British” labels are misleading. As the OED notes, both systems were invented by the French. And both have their merits. The “American” system has the advantage of convenience. It’s easier to say “one billion” than “one thousand million”. On the other hand, etymologically, there is something to be said for the “British” system. A billion is the second power of a million (a million times a million), a trillion is the third power and so forth. This fits in with the bi- and tri- prefixes.

In Britain, people use both systems and this can and does cause confusion. It’s fair to say, however, that the “American” system is being used more and more and the “British” system less and less. The UK government has been using the “American” standard since the 1970s. On the whole, the “American” approach is probably the better one to take as it’s what most people will understand. But it may be worth spelling out exactly what you mean by these terms if you find yourself needing to use them.

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7 Responses to “How Much Is A “Billion”?”

  • Robyn Broyles

    This is why scientists use scientific notation!

    I just blogged about the Large Hadron Collider in Europe, which recently fired up its particle beams to a record-high energy of 3.5 x 10^9 electron-volts. That’s 3,500,000,000 electron volts. I wrote it out as 3.5 trillion, using the American or “short” scale, but obviously that can be confusing.

    Scientists really do use phrases like “ten to the ninth” in conversation, but they also have a defined set of prefixes. The prefix for 1,000,000,000 is tera-, so the LHC’s beams’ energy is also written as 3.5 TeV (tera-electron-volts). The world’s second highest energy particle accelerator, in Illinois, is named after its highest possible beam energy of 1 TeV: it’s called the Tevatron.

  • Simon Kewin

    Hi Robyn,

    Thanks for the extra information! I deliberately avoided talking about the powers of 10 as I thought it might make matters less clear, but I take your point.

    The prefixes you describe might make for an interesting further post. I’m a software developer amongst other things and we obviously make use of the same prefixes, but, once again, the meanings are slippery. In computing terms, a “terabyte” could mean either 1,000,000,000,000 bytes or 1,099,511,627,776 bytes!

    Incidentally, isn’t the prefix giga- for 10^9?

  • cmdweb

    I appreciate there has been confusion in the past but in the UK now, it’s generally accepted that one billion is one thousand million is 1,000,000,000.

  • Peter

    It’s easier to say “one billion” than “one thousand million”.

    Though “thousand million” is more common, the number does have a name in the “long” (“British”) system: milliard. However, I’ve never actually heard of anyone using the long system…

    I’m a software developer amongst other things and we obviously make use of the same prefixes, but, once again, the meanings are slippery. In computing terms, a “terabyte” could mean either 1,000,000,000,000 bytes or 1,099,511,627,776 bytes!

    AFAIK, “terabyte” in computing terms always means the latter (though the officially-sanctioned term for that is “tebibyte”, TiB), except for disk capacity, where it means 1,024,000,000,000 bytes.

  • Jon

    Once you reach 10^24 the agreed SI prefixes end. with yotta- being the top of the tree so far.

    There is a semi-serious petition to get ‘hella-‘ designated as the SI prefix for 10^27, (see the New Scientist for instance.

    There’s also a less serious (!) counter-petition for establishing the next group of prefixes as “harpo-“, “chico-“, “groucho-” and “zeppo-“.

    The Sun’s output could be measured in ‘hellawatts’, and the distance between very remote stars measured in “zeppo-metres”

  • Peter

    There is a semi-serious petition to get ‘hella-’ designated as the SI prefix for 10^27

    And 10^30 should be dubbed “valotta-” … then 10^810 = 10^27 * 10^30 would be a “hellavalotta”…

  • John

    What is a “thousand million” if it is not a billion! It should be a natural progression from 1,000,000 with each 000, taking you to a billion, 000 trillion etc.

    The Americans have the right idea, their system is more logical. They can borrow money from the UK, pay it back the same day and make a nice profit. 😉

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