What Is the Difference Between Un vs. Uno in Spanish

Written by Diana Luciana

Diana Luciana ran marketing for Speak Better Spanish from 2020 to 2024. She wrote 51 posts on this blog and edited 95 of our YouTube videos. Hannah met Diana while traveling in Peru. They became friends, and when Hannah found out Diana had a degree in marketing, she asked for her help. She is still a good friend of the team.

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February 6, 2021

Un is the word for “a” before a masculine noun: un libro, un café. Uno is the number one, or “one” when the noun is left out: ¿cuántos quieres? Uno. So say un libro, never uno libro. Before a feminine noun, the word for “a” is una: una casa.

Hannah Pinkerton, lead Spanish fluency coach

This lesson comes from Speak Better Spanish, live one-to-one Spanish coaching for adults with Hannah, Arturo and Jacky. Rated 5.0 on Google. Get a free speaking plan →

Un is an indefinite article used in front of masculine nouns: un libro (a book.) Whereas uno is a cardinal number and means “one” in English: uno, dos, tres… These two can be confused because in Spanish we use gendered nouns. Therefore, the indefinite articles (such as un and una) must match the noun’s gender. In addition, you have uno, which is a number (and sounds a bit masculine) that can be easily misunderstood when you take together un, una, and uno.

Let’s delve into it! I’ll explain what each of them is, give you some examples, and then you can practice using un and uno in your Spanish conversations.

Video transcript

Hola, amigos, bienvenidos a este nuevo video de Speak Better Spanish. I'm Hannah. Today, we're going to be talking about what's the difference between "un" and "uno" in Spanish. So, I think a great example of this that really shows the difference is this one. ¿Quieres un libro? Sí, quiero un libro. ¿Cuántos libros quieres? Quiero uno. So, in the first example, quiero un libro, because we have the noun "libro" after "un", that word for "one" which is normally "uno" will change to an "un" because "libro" is a singular masculine noun.

Now, in the second example, when I say "¿Cuántos libros quieres?" "Quiero uno" because after "uno" I don't specifically state any noun, even though it's implied that it is a book. So, that's really the main difference between "uno" and "un" that we're going to see in Spanish. There are some other contexts where they will show up differently, but really we're just going to be looking for that singular masculine noun, and if it comes after "uno", we're going to change it to "un". And in both cases, it means "one" or "a", which is kind of the same in English.

So, I hope that helps you guys with the difference between "uno" and "un". I would love to have you write an example in the comment section below on how to use "uno" and "un" correctly in Spanish. Thanks for watching, guys. I'll see you in the next video. ¡Hola, amigos! Hope you enjoyed this video. If you did, please give it a thumbs up. Be sure to subscribe and turn on that notifications bell, so you'll always stay in the loop when I share a new video. If you have any questions or comments on this video, drop them below.

If you're interested in working with me one-on-one or in a group setting with personalized online classes, you can learn more about that at speakbetterspanish.com. ¡Ciao!

Un and una are indefinite articles

What is an indefinite article? In English, “a” and “an” are known as indefinite articles, and the Spanish equivalents are un (used before a masculine noun) and una (used before a feminine noun). Remember that nouns in Spanish can be classified as masculine and feminine, so you need to use un and una accordingly. Let’s see a few examples:

Un libro – A book
Una bicicleta – A bicycle
Un hombre – A man
Una mujer – A woman
Un carro – A car

Spanish numbers: uno, dos, tres…

Uno is a cardinal number and means “one” in English. Remember that you have cardinal and ordinal numbers; ordinal numbers are the ones such as “first,” “second,” and “third.” Here are a few examples of cardinal numbers in Spanish:

1 – Uno
2 – Dos
3 – Tres
4 – Cuatro
5 – Cinco
6 – Seis
7 – Siete
8 – Ocho
9 – Nueve
10 – Diez

What’s the difference between un and uno?

Un is an indefinite article (“a” or “an”) used in front of Spanish masculine nouns, and uno is a cardinal number meaning “one.” You can easily remember uno vs. un through an example:

¿Cuántos libros quieres? – How many books do you want?
Quiero un libro. – I want a book. / Quiero uno. – I want one.

Frequently Asked Questions

Is it un or uno libro?

Un libro. Before a masculine noun, uno shortens to un. The same happens in numbers: veintiún libros, not veintiuno libros. Uno stays whole only when it stands alone, as in ¿cuántos libros? Uno, or when you count: uno, dos, tres.

When do you use uno in Spanish?

Use uno when you count, when you answer with a number alone, and when the noun is already understood: ¿quieres un taco? Sí, dame uno. It also means “one” as in “someone”: uno nunca sabe, “you never know.”

What is the difference between un and una?

Un goes with masculine nouns and una with feminine ones: un perro, una gata. Both mean “a” or “one.” The plurals are unos and unas, which mean “some”: unos amigos, unas amigas.

Why do people say un agua if agua is feminine?

Feminine nouns that start with a stressed a sound take un in the singular so the two a sounds do not run together: un agua, un águila. The noun is still feminine, so you say el agua fría, not el agua frío.

For more on this, read when to use uno and un in Spanish, and for agreement in general, Spanish plural nouns and poco vs un poco.

Small words like un and uno are where a coach hears what you cannot. If you want that kind of feedback, book a free Spanish Roadmap Session or see conversational Spanish coaching.

Hope you enjoyed today’s lesson! 💜

More examples with un and uno in Spanish

MARLEN: ¡Cecy! Tengo dos boletos para un concierto de rock el sábado. ¿Estarás ocupada?
CECY: ¡Ay, ¿no me digas que es el de AC/DC?
MARLEN: Sí, justo ese. Iba a ir con mi hermano, pero está enfermo y ya no pudimos venderlo y yo no quiero ir sola.
CECY: Yo voy contigo, me encanta AC/DC. Yo también quería ir pero no alcancé boletos. Me has alegrado el día como no tienes idea.
MARLEN: Me imagino, a mi también porque será muy divertido ir con mi mejor amiga.
CECY: Sí, gracias por invitarme.
MARLEN: No pensé que te gustara tanto esa banda. De haber sabido desde un principio hubiera comprado boletos para los tres.
CECY: Sí, es que ya tiene tiempo que no los escucho tanto, pero siempre me han gustado, de hecho tengo un póster firmado por todos, debe valer mucho dinero ahora, me lo regaló mi papá.
MARLEN: Wow, que chido, tengo que verlo, cuando vaya a tu casa me lo tienes que mostrar.
CECY: Sí, claro, está en la oficina de papá, pero ya es mío, por eso es que nunca lo has visto cuando has ido de visita.
MARLEN: Sí, me imagino.

***

CECY: Oye, y ¿qué le pasó a tu hermano?
MARLEN: Tiene infección estomacal, tal vez algo que comió ayer, se siente muy mal y no cree estar bien para mañana, el doctor le dijo que debía guardar reposo.
CECY: Uy, pobre Mario, espero se recupere pronto, espero le hayan recetado un buen antibiótico para que pronto esté mejor.
MARLEN: Sí, al parecer el tratamiento es muy bueno, ya veremos.
CECY: Qué bien, me saludas a tu hermano y dile que gracias por el boleto.
MARLEN: Claro, yo le digo. Nos vemos el sábado. Mi papá pasa por nosotras. Adiós.

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