In Italian, ordinal numbers from 1st to 10th have unique forms (primo, secondo, etc.). But forming ordinals from 11th onwards is much simpler and highly regular.
The Suffix -esimo
To form an ordinal number from 11 upwards, take the cardinal number (like undici or dodici), drop its final vowel, and add the suffix -esimo.
For example, undici (eleven) becomes undicesimo (eleventh).
| My brother finished eleventh in the championship. | Mio fratello è arrivato undicesimo nel campionato. |
Agreement with Nouns
Ordinal numbers act as adjectives. This means the ending must change to match the gender and number of the noun it modifies (-esimo, -esima, -esimi, -esime). In Italian, ordinal numbers almost always come right before the noun they describe.
| This is the eleventh match we have lost. | Questa è l'undicesima partita che abbiamo perso. |
| Today is our thirteenth anniversary. | Oggi è il nostro tredicesimo anniversario. |
Rankings and Standings
These higher ordinal numbers are very common when discussing sports, competitions, and rankings. To talk about rankings, you will often use nouns like il posto (the place), la posizione (the position), and la classifica (the standings).
Notice how the ordinals agree with these nouns to describe exact placements:
| My cousin is in twelfth place in the standings. | Mio cugino è al dodicesimo posto in classifica. |
| The team kept the fifteenth position in the standings. | La squadra ha mantenuto la quindicesima posizione in classifica. |
This pattern remains completely consistent as you count higher, up to 20th (ventesimo) and beyond:
| We celebrated my son's eighteenth birthday. | Abbiamo festeggiato il diciottesimo compleanno di mio figlio. |
| This is the twentieth match of the championship. | Questa è la ventesima partita del campionato. |