Ordinal numbers, as the name suggests, are numbers that indicate the order of nouns in a series. And just like cardinal numbers, ordinal numbers are adjectives. But unlike cardinal numbers, ordinal numbers actually do match the noun they modify in both gender and number, and in most cases, they precede (go before) the noun.
Es el segundo carro que he comprado.
It is the second car that I have bought.
Los primeros días de nuestras vacaciones fueron fantásticos.
The first days of our vacation were fantastic.
Mira la octava página.
Look at the eighth page.
Fuimos las primeras personas invitadas a la fiesta.
We were the first people invited to the party.
Basic Ordinal Numbers 1st-100th
1st
primero (primer)
2nd
segundo
3rd
tercero (tercer)
4th
cuarto
5th
quinto
6th
sexto
7th
séptimo
8th
octavo
9th
noveno
10th
décimo
11th
undécimo
12th
duodécimo
13th
decimotercero
14th
decimocuarto
15th
decimoquinto
16th
decimosexto
17th
decimoséptimo
18th
decimoctavo
19th
decimonoveno
20th
vigésimo
30th
trigésimo
40th
cuadragésimo
50th
quincuagésimo
60th
sexagésimo
70th
septuagésimo
80th
octagésimo
90th
nonagésimo
100th
centésimo
Ordinal numbers 1st-12th
The ordinal numbers 1st-12th should be memorized as they have unique forms. Newer forms, also accepted by the RAE, for 11th and 12th are decimoprimero and decimosegundo , respectively.
Ordinal numbers 13th-19th
The teens are a bit special as they are written as a single word according to the following formula:
multiple of ten (minus any written accents) + 1st-9th
13th - décimo + tercero = decimotercero
15th - décimo + quinto = decimoquinto
19th - décimo + noveno = decimonoveno
Notice that 18th does not follow the pattern since the -o is removed from décimo before adding octavo so that you don’t end up with two -os in a row.
It is also acceptable according to the RAE to write the ordinal numbers 13-29 as two separate words.
13th - décimo tercero
15th - décimo quinto
19th - décimo noveno
Ordinal numbers 21st-99th
The rest of the ordinal numbers below 100 are fairly simple. Write out each successive ordinal number as a separate word.
21st - vigésimo + primero = vigésimo primero
36th - trigésimo + sexto = trigésimo sexto
99th - nonagésimo + noveno = nonagésimo noveno
Ordinal numbers past 100
200th
ducentésimo
300th
tricentésimo
400th
cuadringentésimo
500th
quingentésimo
600th
sexcentésimo
700th
septingentésimo
800th
octingentésimo
900th
noningentésimo
1,000th
milésimo
For ordinal numbers between the multiples of 100, simply follow the previous rules. Write out each successive ordinal number as a separate word.
482nd - 400th + 80th + 2nd = cuadringentésimo octagésimo segundo
177th - 100th + 70th + 7th = centésimo septuagésimo séptimo
¡Ojo! A Few Notes
Formal Usage
Ordinal numbers are most commonly used up to the 10th. The 11th and higher are fairly uncommon and considered formal. For larger numbers, it is actually more common to just use the ordinal number, especially in speech.
Durante el siglo 19...
During the 19th century...
Cumplo 30 años hoy.
It’s my 30th birthday today.
Ending Changes
Know that primero and tercero change to primer and tercer respectively when they precede a singular masculine noun.
Juan está en el tercer piso.
Juan is on the third floor.
el primer hombre
the first man
Abbreviations
Ordinal numbers in English take -st for one (1st), -nd for two (2nd), -rd for three (3rd), and -th for the rest of the numbers (4th, 5th,...). In Spanish you add a decimal and then the superscript o for all numbers, or a if you are counting feminine nouns, and er for shorter versions such as primer (1.er) and tercer (3.er).
primer -> 1.er
segundo -> 2.o
tercera -> 3.a
Placement
In Spanish, cardinal numbers usually precede, or go in front of, the nouns the modify. However, if the noun is royalty, a pope, or a street name, then they go after the noun.
Carlos Quinto
Carlos the 5th
el papa Benedicto Decimosexto
Pope Benedict the 16th
la Calle Octava
8th Street
If both cardinal and ordinal numbers appear together, the cardinal number goes before the ordinal number.
Me encantan las dos primeras escenas.
I love the first two scenes.
Estuve enferma los tres primeros días.
I was sick the first three days.
