1 Billion in French
Un Milliard (Not Un Billion)
Updated May 2026
The headline answer
English 1 billion (10^9) = French un milliard
IPA: /œ̃ mil.jaʁ/ · with audio:
False friend warning
The French word billion does NOT mean what English “billion” means. French billion = 10^12 = English trillion. French milliard = 10^9 = English billion. If you translate English “billion” with French “billion”, you scale the figure by one thousand. This is one of the most consequential false-friend traps in business and finance translation.
France uses the long-scale numerical naming convention. In the long scale, each new -illion suffix is the previous one multiplied by a million, not by a thousand. So million is 10^6, billion is 10^12, trillion is 10^18. The intermediate orders of magnitude (10^9, 10^15, 10^21) get the -illiard suffix: milliard for 10^9, billiard for 10^15, trilliard for 10^21. English in both British and American usage today follows the short scale, where each new -illion is the previous times a thousand: million (10^6), billion (10^9), trillion (10^12).
The result of this scale mismatch is a very specific translation pitfall. When an English-language source says “1 billion”, the French equivalent is un milliard. When an English source says “1 trillion”, the French equivalent is un billion (or, for clarity, mille milliards). Casually mapping English billion to French billion produces a thousand-fold error in the wrong direction.
Long Scale vs Short Scale: The Full Mapping
| Power of 10 | French (long scale) | English (short scale) | SI prefix |
|---|---|---|---|
| 10^6 | un million | one million | M (mega) |
| 10^9 | un milliard | one billion | G (giga) |
| 10^12 | un billion | one trillion | T (tera) |
| 10^15 | un billiard | one quadrillion | P (peta) |
| 10^18 | un trillion | one quintillion | E (exa) |
| 10^21 | un trilliard | one sextillion | Z (zetta) |
The SI prefix column is the same in both languages, which is why scientific French often prefers un téraoctet (1 TB) or un gigaoctet (1 GB) to avoid ambiguity around milliard versus billion. The SI brochure (BIPM) is the international authority for these prefixes.
History of the Long Scale in French
The long scale was actually invented in France in the 15th century, by Nicolas Chuquet in his manuscript Triparty en la science des nombres (1484). Chuquet defined billion = a million millions, trillion = a million billions, and so on, using the powers-of-a-million ladder. This convention spread across continental Europe and became the standard in French, German, Spanish, Portuguese (in Portugal), Italian, Dutch, and Polish.
English originally used the long scale too. Then in the late 19th and early 20th century, American usage shifted to the short scale (where billion = 10^9), and the British Treasury formally adopted the short scale in 1974 to align with American practice. France briefly toyed with the short scale by decree in 1948 but reverted to the long scale by another decree in 1961. The 1961 decree (décret n° 61-501 du 3 mai 1961) is still in force and is what defines French long-scale usage today.
The long-scale forms milliard and billion are documented in the Dictionnaire de l’Académie française. The Légifrance archive holds the 1961 decree text. The OQLF Banque de dépannage linguistique publishes detailed usage notes for long-scale forms in Canadian French.
Worked Examples
| English | French | Note | Audio |
|---|---|---|---|
| English: 1 billion (10^9) | un milliard | False friend with French "billion". | |
| English: 1 trillion (10^12) | un billion | NOT one billion in French; this means 10^12. | |
| 1 billion euros | un milliard d'euros | De required; elision before vowel. | |
| 5 billion people (world ~5 of 10) | cinq milliards de personnes | Plural-s on milliards. | |
| 13.8 billion years (age of universe) | treize milliards huit cents millions d'années | Or 13,8 milliards d'années in compact form. | |
| 35 trillion USD (US debt order) | trente-cinq billions de dollars | In long scale. | |
| Compact: same value | trente-cinq mille milliards de dollars | Often preferred to avoid billion ambiguity. | |
| 1 000 000 000 m | un milliard de mètres (= 1 Gm) | SI giga-prefix; one million km. |
Where Milliards Naturally Appear
National budgets and public debt. The French state budget for 2026 is around quatre cent cinquante milliards d’euros (450 billion euros). The French national debt has been quoted at around trois mille cent milliards d’euros (3.1 trillion euros). Eurozone GDP figures, ECB interventions, IMF programmes are all in the milliards d’euros range. Milliard is the working unit of European fiscal journalism.
World population and global statistics. The world has huit milliards d’habitants as of 2025 (about 8.1 billion). India and China together account for around deux milliards huit cents millions d’habitants. The internet has roughly cinq milliards d’utilisateurs. These figures are all in the single-digit milliards range and pluralise predictably.
Astronomy and cosmology. The age of the universe is around treize milliards huit cents millions d’années (13.8 billion years). Earth is about quatre milliards cinq cents millions d’années old (4.5 billion). The Milky Way contains roughly cent à quatre cents milliards d’étoiles (100 to 400 billion stars). The observable universe has roughly deux mille milliards de galaxies (2 trillion galaxies, given as deux mille milliards rather than deux billions for clarity).
Tech and computing. A modern smartphone has around cinq milliards de transistors in its main processor. The Apple A18 Pro chip carries roughly vingt milliards de transistors. Datacentre storage in petabytes corresponds to milliards d’octets times a thousand. The SI prefix giga (G, 10^9) is exactly equivalent to one milliard, hence un gigaoctet = 10^9 octets.
Translation Cheat Sheet
When translating from English to French at the billion-and-above scale, follow this rule: take the English number, identify the suffix, and substitute the French equivalent according to the long-scale ladder.
- English “million” (10^6) → French million. Same value, same word root.
- English “billion” (10^9) → French milliard. Different word, same value.
- English “trillion” (10^12) → French billion or mille milliards. Same word as English “billion” but very different value; mille milliards is often preferred to avoid confusion.
- English “quadrillion” (10^15) → French billiard or mille billions. Billiard is rarely used in everyday French; the compact mille billions is more readable.
- English “quintillion” (10^18) → French trillion. Again same word, different value.
For technical and scientific publications, switching to scientific notation (3,5 x 10^9) or to SI prefixes (3,5 G) is the cleanest way to avoid the false-friend trap entirely. Major French press and scientific outlets (Le Monde, Pour la Science, La Recherche) routinely use scientific notation alongside written-out forms when reporting figures in the billions and above.
Frequently Asked Questions
How do you say 1 billion in French?
Un milliard. The English word "billion" corresponds to the French milliard (10^9, or one thousand millions). The French word "billion" exists but means something different: it means 10^12, which English calls a trillion. This false-friend trap catches almost every English speaker on first encounter.
Why does French use "milliard" and not just "billion"?
Because French (like German, Spanish, and most continental European languages) uses the long scale, where each new -illion suffix represents a million times the previous: million (10^6), billion (10^12), trillion (10^18), quadrillion (10^24). English (in both modern British and American usage) uses the short scale, where each new -illion suffix represents a thousand times the previous: million (10^6), billion (10^9), trillion (10^12). The intermediate scale-points (10^9, 10^15, 10^21) needed names too in the long scale, hence: milliard, billiard, trilliard.
How do you write 1 billion in French digits?
1 000 000 000, with thin spaces between groups of three digits (nine zeros after the 1). The same value in scientific notation: 1 x 10^9 or simply 10^9. SI prefix: G (giga), as in gigaoctet for 10^9 bytes.
How do you say "1 billion euros" in French?
Un milliard d'euros. The de-preposition (elided to d') is required because the number ends with the noun milliard. National budgets, public debts, ECB and IMF figures are conventionally quoted in milliards d'euros. The French national debt at end-2024 was around 3 100 milliards d'euros, equivalent to 3.1 trillion in English.
How do you say 2 billion, 5 billion, 10 billion in French?
Deux milliards, cinq milliards, dix milliards. Milliard pluralises like any noun. With a counted noun: deux milliards d'euros (2 billion euros), cinq milliards d'années (5 billion years, the rough age of the Earth), dix milliards d'utilisateurs (10 billion users, hypothetical).
When do French speakers actually use the word "billion"?
Rarely, and only in very specific scientific or fiscal contexts where 10^12 needs a single word. The astronomy of the universe (the universe is around 13.8 milliards d'années old, or 0,0138 billion d'années; both are correct but the second is awkward), national debt of largest economies (the US national debt is around 35 billions de dollars, that is 35 x 10^12), and in physics and chemistry sometimes. In everyday French (journalism, business, government), milliard is by far the more common word, and billion is often replaced by "mille milliards" for clarity.
Is the long scale used everywhere in France?
Yes. France formally adopted the long scale in 1948 by decree, after a period (1948-1961) of confusion when an earlier 1948 short-scale form was reconsidered. The long scale (million, milliard, billion = 10^12, billiard, trillion = 10^18) has been the official French standard since 1961. The same long-scale system is used in Belgium, Switzerland, and Quebec. The short scale (where billion = 10^9) is used in English, Brazilian Portuguese, modern Russian, and a few other languages.