The long and short scale
A billion used to mean something different in Britain. Knowing when it changed is the difference between reading an old document correctly and being out by a factor of a thousand.
Two systems
On the short scale, each scale word is a thousand times the one before it: a billion is a thousand million, a trillion is a thousand billion. This is what modern British, American, South African, Australian and Irish English all use, as does Indian English when it counts in millions rather than in lakh and crore. The tools here use it too.
On the long scale, each named word is a million times the one before it: a billion is a million million. The steps in between get their own names ending in -ard, so a thousand million is a milliard.
| Word | Short scale | Long scale | Notes |
|---|---|---|---|
| million | 1,000,000 | 1,000,000 | The two agree here, and nowhere above it. |
| billion | 1,000,000,000 | 1,000,000,000,000 | A thousand million, or a million million. |
| trillion | 1,000,000,000,000 | 1,000,000,000,000,000,000 | The gap widens with every step. |
When Britain changed
British usage was long scale for most of its history. The short scale had been standard in the United States since the nineteenth century, and British finance and journalism drifted towards it through the twentieth as American reporting became the common source for large figures. On 20 December 1974 the Prime Minister, Harold Wilson, said in a written Commons answer that billion was now used internationally to mean a thousand million and that it would be confusing for British ministers to use it in any other sense, though he accepted it could still be read in Britain as a million million.
How to read an older document
- British, before the mid-1970s: a billion can be a million million, and the older the document the likelier that is. Before about 1970, treat it as a million million unless the context clearly says otherwise. Government and scientific sources from the period are the likeliest to be long scale.
- British, since the mid-1970s: short scale. A billion is a thousand million.
- American, any period: short scale throughout.
- Translated from a European language: check. French, German, Spanish, Italian, European Portuguese, Dutch and the Scandinavian languages are long scale today, so a German Billion is a million million and a translator who wrote it as “billion” has changed the figure by a factor of a thousand. Brazilian Portuguese is the exception: it is short scale, and its bilhão is a thousand million, where the European Portuguese bilião is a million million.
What to do when it matters
Write the digits. A figure that has to be unambiguous across languages and decades is written as 1,000,000,000 or as 10⁹, and the words are put next to it rather than instead of it. This is why scientific writing almost never uses billion at all and why financial reporting so often gives both the figure and the word.
The intermediate words are worth recognising even though English does not use them. A milliard is a thousand million and a billiard is a thousand billion, and both turn up in older British writing and in translation.