Un vs Une in French Numbers
The cardinal 1 is the only French number that agrees with the gender of the noun it counts. Inside compounds (21, 31 ... 81, 101) the same rule applies: vingt et un livres for masculine, vingt et une pages for feminine. The Academie francaise has codified this as strict, not optional.
Updated May 2026
| French | English | Note | Audio |
|---|---|---|---|
| un livre | one book / a book | Masculine: livre is masculine. | |
| une page | one page / a page | Feminine: page is feminine. | |
| vingt et un livres | 21 books | Masculine: un agrees with livres. | |
| vingt et une pages | 21 pages | Feminine: une agrees with pages. Both un et un and et une are accepted spellings; the agreement is in the spoken / written ending. | |
| trente et un mois | 31 months | Masculine: mois is masculine. | |
| trente et une semaines | 31 weeks | Feminine: semaines is feminine. | |
| cinquante et un degres | 51 degrees | Masculine: degres is masculine. | |
| soixante et une minutes | 61 minutes | Feminine: minutes is feminine. | |
| soixante et onze euros | 71 euros | Onze is invariable; no gender shift on 71, 91 because onze has no feminine form. | |
| quatre-vingt-une personnes | 81 people | Feminine: personnes is feminine. The vingt-un compound takes une in the feminine. | |
| cent une lignes | 101 lines | Feminine: lignes is feminine. Same agreement holds for 201, 301, 401 ... 1001. |
One number, one rule
Only the cardinal one (un / une) inflects for gender. Every other cardinal is invariable: deux pages, trois pages, dix pages, vingt pages all use the same form. The rule fires inside compounds (21, 31, 41, 51, 61, 81, 101) because the final morpheme is the cardinal one. 71 and 91 are exceptions because they end in onze, which is invariable.
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Frequently asked
Sources: Academie francaise, Larousse, Le Robert.