100 Million in French
Cent Millions, with the Plural-S
Updated June 2026
The headline answer
100 000 000 = cent millions
IPA: /sɑ̃ mil.jɔ̃/ · with audio:
One hundred million in French is cent millions. This form sits at a particular grammatical pinch point: cent is a determiner whose plural-s appears only when it is multiplied by another number, and millions is a noun whose plural-s is unconditional. The result is the slightly counter-intuitive form where cent has no s but millions does. Once you see why, the rule becomes easy to apply across the entire 100,000,000 to 999,999,999 range.
This page covers the rule itself, the noun-versus-numeral distinction that decides when the s survives (deux cents millions but deux cent mille), common contexts where 100 million appears (population, planetary distances, very large monetary sums, geological time), and the most common compounds and worked examples.
The Cent-Loses-S Rule
The rule for the plural-s on cent is documented in the Dictionnaire de l’Académie française and goes like this. Cent takes a plural-s if it is multiplied by another number AND no other numeral follows. So you write deux cents for 200 (multiplied by deux, nothing follows, s appears) and quatre cents for 400. But you write deux cent un for 201 because the numeral un follows; the multiplication is no longer the final operation, so the s drops. The same applies to deux cent mille (200,000), trois cent mille, etc. As soon as another numeral appears after cent, the s comes off.
In cent millions the cent has no s for a simpler reason: it is not multiplied by anything. The standalone cent never displays a plural-s in the first place. So cent millions reads as “hundred millions” in literal English: cent quantifies how many groups of one million there are.
For a multiplied form like 200 million, you write deux cents millions with the s. Million and milliard are nouns, not numerals, so they do not trigger the s-drop: the multiplied cent still ends the numeral part of the expression. The OQLF Banque de dépannage linguistique gives cinq cents millions de dollars as its worked example. The 1990 rectifications changed the hyphenation of compound numbers, not this agreement rule.
Why Millions Always Keeps Its S
Million is in the noun class, the same grammatical category as milliard, billion, douzaine, centaine. Nouns pluralise the moment they refer to a count greater than one. Five hundred million is cinq cents millions, with millions taking the plural-s because the count is plural, full stop. There is no “another numeral follows” conditional rule for nouns; the conditional rule applies only to determiners.
The same logic is what produces deux mille cinq cents (2,500: cents keeps its s because nothing follows) but deux mille cinq cent un (2,501: cent drops its s because un follows). And deux millions always has the s. And deux mille millions would have mille invariable (mille never pluralises) and millions with the s.
The asymmetry is unusual but it is internally consistent. Determiners (vingt, cent, mille) belong to the number system. Nouns (million, milliard, douzaine) belong to the noun system. They follow their own respective rules.
Worked Examples
| Number | French | Note | Audio |
|---|---|---|---|
| 100 million | cent millions | Cent is not multiplied, so no s; millions keeps its s. | |
| 100 million euros | cent millions d'euros | De required; elision before vowel. | |
| 200 million | deux cents millions | Multiplied cent keeps its s before the noun millions. | |
| 500 million people | cinq cents millions de personnes | De required; no elision before consonant. | |
| 150 million | cent cinquante millions | Cent without s; cinquante is invariable. | |
| 100,000,000 km | cent millions de kilomètres | Astronomy and physics; SI digit grouping. | |
| 100,500,000 | cent millions cinq cent mille | No de inside the count; segments concatenated. | |
| 100,000,001 | cent millions un | Final un attaches without et; et only at the units position of round tens. |
Where 100 Million Naturally Appears
Astronomy. The Sun-Earth distance averages cent cinquante millions de kilomètres (one astronomical unit). The Moon orbits at roughly trois cent quatre-vingt mille kilomètres from Earth, so the Sun is about four hundred times further. Mars at perihelion is about cinquante-cinq millions de kilomètres away, swinging out to quatre cents millions de kilomètres at aphelion. Planetary distances from the Sun are conventionally given in millions of kilometres, so the cent-millions form turns up regularly in popular astronomy writing.
Population. The European Union has roughly quatre cent quarante millions d’habitants (440 million inhabitants). The United States has about trois cent quarante millions d’habitants. The figure 100 million serves as a natural unit when discussing continental-scale demographics and is the threshold beyond which a country counts as one of the world’s most populous (currently 14 such countries).
Geological time. The dinosaurs went extinct around soixante-six millions d’années ago, at the K-Pg boundary. The last common ancestor of humans and chimpanzees lived around six millions d’années ago. The Cambrian explosion was around cinq cent quarante millions d’années ago. The unit million-of-years (Ma in scientific notation) is foundational to French popular geology and palaeontology writing.
Cinema and music. A French film grossing cent millions d’euros at the box office (about 110 million USD) is a major commercial success; only a handful of releases hit that threshold each year. A song with cent millions de vues on YouTube enters the territory where it would chart globally. The unit cent millions has natural cultural resonance as the threshold for “global hit”.
Mistakes English Speakers Make at the 100 Million Threshold
Putting an s on cent. Cents millions is wrong for 100 million. Write cent millions: the s is a multiplication marker, and this cent is not multiplied by anything. (When cent IS multiplied, the s stays before millions: deux cents millions.)
Dropping the s on millions. Cent million singular is wrong. Million is a noun and pluralises whenever the count is plural. Cent millions always has the s.
Forgetting de before counted nouns. Cent millions habitants is wrong. The number ends with the noun millions, so de is required: cent millions d’habitants.
Comma instead of space for digit grouping. 100,000,000 is the English typographic convention. French uses thin space: 100 000 000. The comma in French is the decimal separator only.
Frequently Asked Questions
How do you write 100,000,000 in French?
Cent millions. Numerically: 100 000 000 with thin spaces between groups of three digits. Note that "cent" loses its plural-s here because "millions" follows it; the s on cent only appears when cent is multiplied and is the last counting word in the number.
Why is it "cent millions" and not "cents millions"?
Because the s on cent is a multiplication marker, and in cent millions the cent is not multiplied by anything: it is just one hundred. Cent only takes the s when it is multiplied AND no other numeral follows: deux cents (200), trois cents (300), quatre cents (400), but deux cent un (201) and trois cent mille (300,000). When cent IS multiplied before millions, the s actually stays (deux cents millions), because million is a noun rather than a numeral.
Why does "millions" keep the s in "cent millions"?
Because million is a noun, not a determiner. Nouns pluralise according to ordinary noun-plural rules: one million, two million, a hundred million all require the plural-s on millions. The s on millions is unconditional whenever the count is greater than one.
How do you say 100 million euros in French?
Cent millions d'euros. The de-preposition (elided to d' before the vowel) is required because the number ends with the noun millions. Without de, the sentence is ungrammatical. The same rule produces cent millions de personnes (100 million people), cent millions de tonnes (100 million tonnes).
How do you say numbers like 200 million, 500 million, 800 million?
Deux cents millions (200 million), cinq cents millions (500 million), huit cents millions (800 million). Here cent keeps its plural-s: million is a noun, not a numeral, so the multiplied cent still ends the numeral part of the expression and the s stays. The same logic gives quatre-vingts millions. Contrast deux cent mille (200,000), where the numeral mille follows cent and the s drops. The 1990 rectifications changed only the hyphenation of compound numbers, not this agreement rule.
What does "cent millions" look like written out in figures?
100 000 000. Eight zeros after the 1, grouped with thin spaces in three-digit segments. In French scientific notation: 1 x 10^8 or 10^8. The exponent form is preferred in physics, astronomy, and population statistics where the number is approximate.
What is the difference between "cent millions" and "cent fois million"?
Cent millions is the standard form for 100,000,000. Cent fois million ("a hundred times one million") is a circumlocution sometimes used in pedagogical or rhetorical contexts to emphasise the magnitude. It is not a standard numerical form. Always use cent millions for actual quantities.