Un vs una in Spanish: which ‘a’ to use

Spanish has two words for “a” or “an”. Use un with masculine nouns and una with feminine nouns. The choice follows the gender of the noun, exactly like the definite article el and la, so the best habit is to store each noun with its gender from the start.

The word “a / an” Use with Example
un masculine singular noun un libro, un cochea book, a car
una feminine singular noun una mesa, una casaa table, a house

Use the noun’s gender, not the English

English “a” gives you no clue about gender, so you read it off the Spanish noun. Endings help with a first guess: most -o nouns are masculine and most -a, -ción, -dad nouns are feminine.

un perro, un problema, un hotel
a dog, a problem, a hotel

una flor, una canción, una ciudad
a flower, a song, a city

Un before a stressed a-sound, still feminine

A feminine noun that begins with a stressed a- or ha- takes un in the singular for easier pronunciation, but it stays feminine.

un águila, un área pequeña
an eagle, a small area

Notice the adjective keeps the feminine form: un área pequeña, not un área pequeño.

Unos and unas mean “some” or “a few”

Spanish has a plural of the indefinite article. Unos and unas translate as “some”, “a few” or “a couple of”.

unos libros, unas mesas
some books, some tables

Tengo unas preguntas.
I have a few questions.

When Spanish drops “a” entirely

Spanish often leaves out un / una before an unmodified profession or after no… ningún. This is normal, not an error.

Soy profesora.
I am a teacher.

No tengo coche.
I don’t have a car.

Common mistakes

Matching the article to the English word

The gender comes from the Spanish noun, never from “a / an”.

una problema → un problema
a problem

Using una before a stressed a-sound

A stressed a- at the start pulls in un, even for a feminine noun.

una águila → un águila
an eagle

Adding “a” before a plain profession

After ser, an unmodified job usually drops the article.

Ella es una doctora. → Ella es doctora.
She is a doctor.

The masculine/feminine split here is the same one you meet with the definite article el vs la; once the gender is set, it also drives possessive choices like mi, tu, su. In Fluera you see the article and noun together in real sentences, so the gender sticks as one unit. Try that when you practice Spanish rather than learning genders from a bare list.

Practice

Un or una?

Question 1 of 10

Quiero ___ café. (masculine -é)

Frequently asked questions

When do I use un and when una in Spanish?
Use un before a masculine noun and una before a feminine noun: un libro, una mesa. The gender of the noun decides, so learn each noun with its gender; endings help, since most -o nouns are masculine and most -a, -ción and -dad nouns are feminine.
Why is it "un águila" if águila is feminine?
A feminine noun starting with a stressed a- or ha- takes un in the singular just for sound: un águila, un área. The noun stays feminine, so the adjective is feminine too: un área pequeña.
What is the plural of un and una?
Use unos and unas, meaning "some" or "a few": unos libros, unas mesas.