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Numbers in Spanish: How to form and write them?

A group of young people sitting on grass talking and laughing.

If you’ve been learning Spanish for a while, you’ve probably studied the numbers. Cardinal numbers, like uno (one), and ordinal numbers, like primero/primera (first), are used in Spanish for different purposes and each group follows their own spelling rules. Read on if you want to learn more about numbers in Spanish.

Table of Contents

What are cardinal numbers?

These are the numbers we use to show quantity. When we say, “Tengo tres libros en mi mochila” (I have three books in my backpack), the word tres (three) is the cardinal number.

How to use cardinal numbers in Spanish?

Cardinal numbers in Spanish can be used for much more than counting. You can use them for prices, dates and years, the hour, age, statistics (including percentages), measurements, weight, and distance:

Mil estudiantes tomaron la prueba.
One thousand students took the test.

El pueblo está a dos kilómetros de aquí.
The town is two kilometers from here.

Check out this table with more uses of cardinal numbers in Spanish and examples.


When reading four digit numbers (whether for years, prices, or quantities), in Spanish it’s not possible to refer to them in hundreds like in English.

fourteen forty-five,
fourteen hundred and forty-five
mil cuatrocientos cuarenta y cinco
one thousand four hundred and forty-five

Saying something like “catorce cientos” (fourteen hundred) is not possible in Spanish. Instead, start stringing the numbers together, starting with the thousands (mil), followed by the hundreds (cuatrocientos), and finally the tens (cuarenta y cinco).

Punctuation and cardinal numbers in Spanish

When writing numbers, commas are used to separate the integer from the decimals. The use of the decimal point, typical of the English language, is also accepted in some varieties of Spanish:

Saqué 6,1 en el examen.
(seis coma uno)
Saqué 6.1 en el examen.
(seis punto uno)
I got 6.1 on the test.

To separate thousands, Spanish uses a full stop or simply a space instead of a comma:

Hay 1.700 personas.
(mil setecientas)
Hay 1 700 personas.There are 1,700 people.

⤷TIP The countries (Mexico, Dominican Republic, and most of Central America) that use the full stop as decimal points will use the comma to separate the thousands; basically they use the same system as English.

Important considerations

  • Uno vs. un and una

    When we use the numbers uno and una (one) or numbers ending in –uno and –una, we need to consider gender agreement. Consider the following rules:

    1. Numbers that end in -uno (like 21, 31, and so on) drop the -o when followed by a masculine noun:

      Miguel tiene veintiún años.
      Miguel is twenty-one years old.

      Note that we dropped the -o from the number veintiuno (twenty-one), but we also added an accent mark to the last vowel.

    2. A number ending in -uno doesn’t change to -un if there’s no noun that follows:

      ¿Cuántos niños hay en la sala? – Veintiuno.
      How many children are there in the classroom? – Twenty-one.

      But, if we add a noun, then we need to apply rule one above:

      ¿Cuántos niños hay en la sala? – Veintiún niños.
      How many children are there in the classroom? – Twenty-one children.

    3. Numbers ending in -uno or -una agree in gender with the following noun:

      Treinta y un hombres
      Thirty-one men

      Treinta y una mujeres
      Thirty-one women

  • Use of conjunction y

    Different from English, in Spanish we use the conjunction y (and) only to separate tens and units:

    Hay cincuenta y dos personas en línea.
    There are fifty-two people online.

    Ella nació en mil novecientos setenta y siete.
    She was born in nineteen seventy-seven.


Numbers from 16 to 19 and all the 20s use the letter “i” and not the conjunction “y” to separate tens and units:

19 = diecinueve
25 = veinticinco

  • Numbers that are written in one word

    In Spanish, some numbers are written in one word only. Numbers from 0 to 30 follow this rule, as well as integer multiples of 10 and integer multiples of 100:

    Juanita tiene veintitrés años.
    Juanita is twenty-three years old.

    Este teatro tiene capacidad para doscientas personas.
    This theater has a capacity of two hundred people.

    Check out the full list of Spanish numbers written in one word here.

The numbers 16, 22, 23, and 26 are written with an accent mark in the last syllable: 

  • 16 = dieciséis
  • 22 = veintidós
  • 23 = veintitrés
  • 26 = veintiséis
  • Gender agreement with compounds of ciento

    Gender agreement is also applicable to compounds of ciento (one hundred). Compare:

    Quinientos kilos
    Five hundred kilos

    Quinientas libras
    Five hundred pounds

  • Cien vs. Ciento

    The word cien refers to the number “one hundred.” We can use this word before a noun and before other numbers such as: mil, millón, billón, trillón, etc.

    Cien personas postularon a la beca.
    One hundred people applied for the scholarship.

    El proyecto tendrá un costo de cien mil millones.
    The project will have a cost of one hundred billion.

    The word ciento also refers to the number “one hundred,” but it’s used with numbers from 101 to 199:

    Hay ciento treinta y cuatro personas interesadas en el curso.
    There are one hundred and thirty-four people interested in the course.


Remember that, unlike English, in Spanish we don’t use “un” in front of cien and mil:

100 = cien (one hundred)
1000 = mil (one thousand)

  • Millón, billón, and trillón

    Millón refers to the word “million” in English. When saying “one million,” remember to follow the indefinite article rule: drop the -o in uno, like this:

    Uno millón. 
    One million.

    When you add a noun after the number, you need to add the preposition de (of):

    Un millón de personas vieron el partido.
    One million people watched the game.


Let’s talk about larger numbers. Did you know the word billón doesn’t mean “billion” in English? In Spanish, it means “one million of millions,” or one plus 12 zeros, which is equivalent to a trillion in English.

Something similar happens with trillón; it means “a million of billions” (one plus 18 zeros). In English it’s equivalent to a quintillion!

In both cases, billón and trillón follow the same rules as millón:

Quisiera tener un billón de dólares.
I would like to have a trillion dollars.

What are ordinal numbers?

These are the numbers we use to indicate order. When we say something like “El ciclista colombiano llegó en segundo lugar” (The Colombian cyclist arrived in second place), the word segundo (second) is the ordinal number.

How to use ordinal numbers in Spanish?

In Spanish, ordinal numbers from one to 10 are common in everyday language. After 10, the ordinal versions tend to be replaced by the cardinal numbers:

Celebramos nuestro treinta aniversario de bodas.
We celebrated our thirtieth wedding anniversary.

If you’re not sure that you know ordinal numbers in Spanish, we’ve got you covered with this list.

Just as with cardinal numbers, there are some special considerations with ordinal numbers in Spanish:

  • They agree in gender and number with the noun they modify and they are typically placed before the noun:

    Vivo en el segundo piso.
    I live on the second floor.

    Vivo en la segunda casa.
    I live in the second house.

  • The ordinal numbers primero (first) and tercero (third) drop the final -o before a masculine singular noun and become primer and tercer:

    ¿Cuál es tu edificio? – El tercero.
    Which is your building? – The third one. 

    ¿Cuál es tu edificio? – El tercer edificio.
    Which is your building? – The third building.

  • When you have cardinal and ordinal numbers together in the same sentence, cardinal numbers go first:

    ¿Tienes las tres primeras respuestas?
    Do you have the first three answers?

  • With proper names ordinal numbers go after the noun:

    Carlos V (quinto)
    Charles V (the fifth)

If you want to review the position of adjectives in Spanish (including ordinal numbers), check out this post.

Primero (first) is the only ordinal number that can be used in Spanish for dates: 

Su aniversario es el primero de marzo.
Their anniversary is on March first

It’s also possible to use the cardinal number. This is the preferred way in Spain: 

Su aniversario es el uno de marzo.
Their anniversary is on March first.

Running out of space? It’s possible to abbreviate ordinal numbers in Spanish in a very easy way: 

primero → 1.º primera → 1.ª

You can do this with any other number. For example: undécimo → 11.º; vigesimoquinta → 25.ª

For primer and tercer (and their compounds) do this: 

primer →
tercer →

This covers the basics, but numbers can also be expressed in fractions and multiplicatives. In Spanish, they are very interesting since they can be used as nouns or adjectives. To know more about this, check out “How to use fractions and multiplicatives in Spanish?

To sum up

As you can see, numbers in Spanish require a bit of attention. Remember: we use cardinal numbers to express quantity and ordinal numbers to express order. There are some spelling rules you need to remember for both, but with enough practice you’ll get there! 

Speaking about practicing, here’s an exercise for you. ¡Adiós!

Are you interested in learning more about Spanish Grammar? Check out our Spanish Grammar Homepage.
Meet The Author:
Natalia Molina
Natalia Molina Ceballos
Spanish Coach
Natalia is a Spanish coach at Mango Languages.

To embark on your next language adventure, join the Mango fam!

Extra Resources:

Numerals in Spanish
Ordinal Numbers


Numerals activity


Numerals activity

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