What is a billion?

Tell a man that there are 400 billion stars and he'll believe you. Tell him a bench has wet paint and he has to touch it to make sure.

We use the word billion so unhesitatingly in the English language, without thinking that a billion is something too huge for the majority of human minds to comprehend.

The original meaning of the word billion is a bit complex. The prefix bi- means two, and the suffix -illion comes from the word million. But the origin of million itself is obscure. The prefix milli- means thousand and the Old French word million just meant a very big thousand. In those days, counting so many thousands of anything was not common and people had little interest in identifying large numbers so precisely.

But these days we use billions of many things. For example, in 2005 the U.S. military used 1.79 billion rounds of ammunition. (source: US Government Accountability Office)

So how big is a billion?

The following may surprise you.

The following is based on the standard international definition of the word billion, which is one thousand-million (10⁹ = 1,000,000,000).

You might have started reading this page around 30 seconds ago. Can you guess how long ago one billion seconds was?

A billion seconds ago it was 10:45 AM Tuesday 4th of July 1978. (Were you alive one billion seconds ago?)
A billion minutes ago takes us back to the days of the Roman Empire - 109 AD.
A billion hours ago was 112,067 BC and our Neanderthal predecessors were hunting mammoth.
A billion dollars ago was 17 hours, at the rate Washington spends taxpayers' money to kill people (source: US Government website: http://www.cia.gov/cia/publications/factbook/geos/us.html#Military.)¹. That's over $16,000 every second!

So when we talk in these web pages about a billion, we really mean a number that's

The original French definition of million-million (10¹²) was adopted by other European countries, notably England and Germany, and spread around the world through European colonialisation. Later, Italian and French scientists and academics realised that this huge number had no practical use, and modified the definition to a thousand-million (10⁹). Britain and Germany retained the original definition, and it was at this time that America chose the French definition (10⁹), along with many other French-rather-than-British influences after the American Revolution War.

For compatibility with its European neighbours, Italy and France reverted to million-million in 1948. But some thirty years later in Britain, thousand-million was adopted as the official billion for government statistics.

So how big is a billion?

Well, in many cases, both million and billion have the same meaning. That is, a huge number that most humans minds cannot comprehend. So you can safely use either.
Or if you want to show off, you could use the word milliard, which means a thousand-million.
However, if you want to be precise and avoid any misunderstanding, it's best to avoid the word altogether and say 'thousand-million' or 'million-million'. Otherwise, as a gentleman named Alastair kindly pointed out to us recently, you run the risk of being over-charged for something: a US billion is worth only 0.1% of a European billion!

1 : The US Military budget for 2007 was $532.8bn. This excluded nuclear weapons research and production, and also excluded the wars in Afghanistan and Iraq ($120bn for 2007). Who got that money?

The United Nations has estimated that for less than one tenth of that budget, clean water, adequate food, sanitation, and basic education could have been provided for every person on the planet. (See the United Nations Development Program.) That money would not, of course, have gone into the coffers of the arms industry.

"Every gun that is made, every warship launched, every rocket fired, represents, in the final analysis, a theft from those who hunger and are not fed, who are cold and are not clothed. This world in arms is not spending money alone. It is spending the sweat of its laborers, the genius of its scientists, the hopes of its children."

Dwight D. Eisenhower, 34th president of US 1953-1961