Spanish indefinite articles are un (masculine singular), una (feminine singular), unos and unas (plural: some, a few, or 'about' with numbers). They agree with the noun. The key difference from English is when to drop them: after ser with a profession (soy profesor), in negatives with tener (no tengo coche), and before otro, cien and mil.
un / una = a, an · unos / unas = some, a few, about- Un, una, unos, unas
- 'A / an / some' in Spanish
- When to drop the article
Un, una, unos, unas: the Spanish words for "a", "an" and "some". The forms take five minutes. What takes my students weeks is the opposite problem — learning when Spanish indefinite articles are not there. Soy profesor. No tengo coche. Otro café, por favor. Three sentences, three places where English needs "a" and Spanish refuses it.
This guide gives you the four forms, the situations where Spanish drops the article, the special meaning of unos and unas, and how the whole family differs from el, la, los, las.
The big pictureWhen to use Spanish indefinite articles
The indefinite article introduces something new or unspecified — one item out of many, when the listener does not yet know which one. Busco un hotel cerca de la playa. (I'm looking for a hotel near the beach.) Any hotel, not a particular one.
Its three everyday jobs:
- First mention — Hay una farmacia en la esquina. (There's a pharmacy on the corner.) After that, it becomes la farmacia.
- One of a kind, not specified — Necesito un adaptador. (I need an adapter.)
- Some / a few (plural) — Compré unas postales. (I bought some postcards.)
And one job English does not have: unos / unas + a number = "about". El taxi cuesta unos veinte euros. (The taxi costs about twenty euros.) Vive a unas dos horas de aquí. (She lives about two hours from here.) Native speakers use this constantly, and it is the easiest way to sound natural when you are not sure of a figure.
The formsHow to form Spanish indefinite articles: un, una, unos, unas
Like every article in Spanish, the indefinite article agrees with the noun in gender and number:
| Masculine | Feminine | |
|---|---|---|
| Singular (a, an) | un — un billete (a ticket), un compañero (a coworker) | una — una reserva (a reservation), una sobrina (a niece) |
| Plural (some, a few) | unos — unos billetes, unos compañeros | unas — unas reservas, unas sobrinas |
The gender of the noun is the same one you learned with el/la. Feminine nouns starting with a stressed a- take un for sound: un águila, un aula — but the noun stays feminine.
When to drop the indefinite article
This is the section to bookmark. In each case below, English needs "a" or "an" and Spanish uses nothing:
- After ser with a profession, nationality, religion or political affiliation. Soy profesor. (I'm a teacher.) Es mexicana. (She's Mexican.) Son católicos. (They're Catholic.) The noun works like a label, so it needs no article. Add an adjective and the article comes back: Es una profesora excelente. (She's an excellent teacher.)
- With tener, haber and buscar when you mean "any at all". No tengo coche. (I don't have a car.) ¿Tienes hermanos? (Do you have any siblings?) No hay problema. (There's no problem.) Busco trabajo. (I'm looking for a job.) These are the forms of tener you will use most, and most of the time they come without an article.
- Before otro, cien, mil, medio, cierto, tal and qué. These words already contain the idea of "a": otro café (another coffee), cien personas (a hundred people), mil gracias (a thousand thanks), media hora (half an hour), ¡Qué día! (What a day!)
- After sin and con in set phrases. Salió sin paraguas. (He left without an umbrella.) Una habitación con baño. (A room with a bathroom.)
- Before plural nouns used in a general sense. Just like English, Spanish drops the article when you are not counting anything specific: Tengo amigos en Madrid. (I have friends in Madrid.) Trabajo con clientes internacionales. (I work with international clients.) Bring back unos/unas only when you mean "a few," not "some in general": Tengo unos amigos que hablan inglés. (I have a few friends who speak English.)
When you feel the urge to say "a", ask: am I classifying (what kind of thing is this person?) or counting (one of them)? Classifying → no article: soy médico. Counting → article: hay un médico en el edificio. Nine times out of ten, that one question gives you the right answer.
In real lifeSpanish indefinite articles in real sentences
From the classroomCommon mistakes English speakers make with un, una, unos, unas
- Soy un profesor. This is the mistake that marks a beginner instantly. With a bare profession, drop it: Soy profesor. Keep the article only when you describe the professional: Soy un profesor paciente.
- Una otra / un otro. English "another" contains "an", so students translate both halves. Spanish uses otro alone: otro día, otra vez (another day, another time).
- Un cien, un mil. Cien and mil mean "a hundred" and "a thousand" by themselves: cien dólares, mil personas. (Note that un millón does take the article.)
- Keeping the article in a negative. Tengo un coche is fine when you mean one specific car. But when you mean "no car at all", drop it: No tengo coche, not no tengo un coche.
- Una before a stressed a-. Una aula → un aula, una águila → un águila. Same sound rule as el agua; the noun is still feminine, so un aula pequeña.
The siblingIndefinite vs definite articles: un café or el café?
Both families agree with the noun; the difference is what they say about it. The indefinite article introduces (a, one of many, some); the definite article identifies (the one we both know, or the thing in general):
| Situation | Indefinite | Definite |
|---|---|---|
| First mention → later mention | Vi una película. (I saw a movie.) | La película era larga. (The movie was long.) |
| One of many → the one we know | Quiero un café. (I want a coffee.) | Me gusta el café. (I like coffee, in general.) |
| Some → the specific ones | Traje unos documentos. (I brought some documents.) | Traje los documentos. (I brought the documents.) |
| English has "a", Spanish has nothing | Soy ingeniera. (I'm an engineer.) | — |
Notice the mirror image. The definite article shows up where English has none (me gusta el café, los lunes), while the indefinite article disappears where English insists on "a" (soy profesor). The gender rules, the -ma exceptions and the contractions al and del all live in the guide to Spanish definite articles; once you know a noun's gender, both families come for free.
Articles are the first building block of basic Spanish grammar, and this pair — when to add "the", when to drop "a" — is where English speakers gain the most from a few minutes of attention. From here, the natural next step is ownership: Spanish possessive adjectives follow exactly the same agreement logic.
PracticeQuick quiz: spanish indefinite articles
Six questions from the lesson. Answer in your head, then open to check.
