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In most English-speaking countries today, one billion equals 1,000,000,000, or 109, or one thousand millions. This is also the convention adopted by Wikipedia.

In most other countries, a word similar to "billion" indicates 1,000,000,000,000, or 1012, or one million millions. For example: French, Norwegian and German billion, Spanish billón, Italian bilione and Swedish billion or biljon. The value 109 is called something similar to the English word "milliard" in these countries. For example, French and Norwegian milliard, German Milliarde, Spanish millardo, Italian miliardo and Swedish miljard or milliard. (Spanish commonly uses "thousand million": mil millones.) See also False friends.

Origin late 17th century: From French, prefix bi- (twice) and -illion (from million). In imitation of one million million. Trillion: one million million million and so on.

Britain and Australia traditionally employed the international usage of 1012, but have recently largely switched to the U.S. version of 109.

Some non-English speaking countries are exceptions to the above rule and match the U.S. usage. A Brazillian Portuguese dictionary indicates 1012 = trilhão, 109 = bilhão. Similarly, transliterating from Greek, 1012 = trisekatommyrio, 109 = disekatommyrio (see myriad).

Table of contents
1 History
2 See also
3 Sources


In 1484 the French mathematician Nicolas Chuquet wrote in his article "Triparty en la science de nombres":
Au lieu de dire mille milliers, on dira million, au lieu de dire mille millions, on dira byllion, etc..., et tryllion, quadrilion...octylion, nonyllion, et ainsi des autres si plus oultre on voulait procéder.

Instead of saying thousand thousands, one will say million, instead of saying thousand million, one will say billion, etc..., and trillion, quadrillion, ..., octillion, nonillion, and similar as far as you want to proceed.

Around 1550 it seems that a Mr Pelletier introduced a second system, the term "milliard". This new system was used in England and Germany and part of the rest of Europe, but USA and France itself did not change to the new word.

Then it became really complicated:

But there seems still to be uncertainty about this:

On one side, Graham Dane, a native English speaker, writes in the forum of the Online-vocabolary

The term milliard is very rare in British English. Billion has meant thousand million in financial writings for many years now, and is almost universal in other fields. Anyone using billion to mean million million is likely to be misunderstood.

On the other side, in the FAQs of alt.usage.english (the part by Ken Moore) states:
Despite this, the U.S. meaning is still rare outside journalism and finance, its introduction having served merely to create confusion. Throughout the U.K., a common response to the question "What do you understand by 'a billion'?" would be: "Well, I mean a million million, but I often don't know what other people mean." Few schoolchildren are confident of the meaning, though, again, 1012 seems to be preferred.

One alternative approach is to use SI prefixes, that is, "Giga" for 109 and "Tera" for 1012. However, this alternative is often only used with specific units that commonly have such magnitudes. An additional problem is that if the unit is a computing term, the term may be interpreted as being a power of 2 instead of a power of 10 (see Binary prefix for more information on one approach to avoiding this).

See also