Italian numbers are divided into two main groups: cardinal numbers (numeri cardinali) and ordinal numbers (numeri ordinali). Cardinal numbers tell us how many people or things there are, while ordinal numbers tell us their position in a sequence. For example, tre means three, but terzo means third. Both types are common in everyday Italian, especially when talking about prices, ages, dates, addresses, and the order of people or things.
Cardinal Numbers
Cardinal numbers are used to count people and things or express quantities. The basic numbers from zero to twenty are worth learning because they form the foundation for larger numbers. Most cardinal numbers do not change according to gender. However, when uno is used directly before a noun, it follows the same pattern as the indefinite article, with forms such as un libro, uno studente, and una casa. When used on its own, uno remains unchanged.
Ho due fratelli. — I have two brothers.
Ci sono tre persone. — There are three people.
Ho venti euro. — I have twenty euros.
After twenty, Italian forms many numbers by combining tens and units. For example, venti (twenty) and due (two) form ventidue (twenty-two). The main tens are trenta (30), quaranta (40), cinquanta (50), sessanta (60), settanta (70), ottanta (80), and novanta (90). In these tens, from venti to novanta, the final vowel is dropped before uno and otto, producing forms such as ventuno (21) and ventotto (28). The same pattern applies to other tens, such as trentuno (31) and trentotto (38). Larger numbers include cento (100) and mille (1,000), which becomes -mila in numbers such as duemila (2,000).
venti + due → ventidue — twenty-two
venti + uno → ventuno — twenty-one
trenta + otto → trentotto — thirty-eight
Ordinal Numbers
Ordinal numbers indicate the position of someone or something in an order, such as first, second, or third. The first ordinal numbers have their own forms, including primo (first), secondo (second), and terzo (third). Unlike cardinal numbers, ordinal numbers behave like regular adjectives ending in -o: they change to agree with the noun in gender and number. For example, primo becomes prima, primi, or prime, depending on the noun. Ordinal numbers usually appear before the noun and are commonly used with a definite article.
il primo giorno — the first day
la seconda settimana — the second week
il terzo piano — the third floor
le prime pagine — the first pages
From eleven onward, ordinal numbers are generally formed with the ending -esimo, although some forms require small changes. For example, undici becomes undicesimo (eleventh), venti becomes ventesimo (twentieth), and ventuno becomes ventunesimo (twenty-first). These forms follow the same agreement rules as other ordinal adjectives.
Summary of Italian Cardinal and Ordinal Numbers
| Number | Cardinal | Ordinal (masculine) | English ordinal |
| 1 | uno | primo | first |
| 2 | due | secondo | second |
| 3 | tre | terzo | third |
| 4 | quattro | quarto | fourth |
| 5 | cinque | quinto | fifth |
| 6 | sei | sesto | sixth |
| 7 | sette | settimo | seventh |
| 8 | otto | ottavo | eighth |
| 9 | nove | nono | ninth |
| 10 | dieci | decimo | tenth |
| 11 | undici | undicesimo | eleventh |
| 12 | dodici | dodicesimo | twelfth |
| 13 | tredici | tredicesimo | thirteenth |
| 14 | quattordici | quattordicesimo | fourteenth |
| 15 | quindici | quindicesimo | fifteenth |
| 16 | sedici | sedicesimo | sixteenth |
| 17 | diciassette | diciassettesimo | seventeenth |
| 18 | diciotto | diciottesimo | eighteenth |
| 19 | diciannove | diciannovesimo | nineteenth |
| 20 | venti | ventesimo | twentieth |