Articles: a / an and When to Use Each

Level: A1. A and an are the same little word in two shapes. The only choice you have to make is which shape fits the next word — and the answer depends on how that word sounds, not how it is spelled.

The rule

A and an are the indefinite article: you use them to talk about one of something when it is new to the conversation or when it does not matter exactly which one — I need a pen (any pen). An article is a small word that comes before a noun to show whether it is specific or general.

Here is the whole rule:

• Use a before a word that starts with a consonant sound: a dog, a car, a house.
• Use an before a word that starts with a vowel sound: an egg, an apple, an idea.

The trap is that English spelling and English sound do not always agree. What counts is the first sound you say, not the first letter you write. So a word spelled with a vowel can take a (a university, because it starts with a “yoo” sound), and a word spelled with a consonant can take an (an hour, because the h is silent and you start with a vowel sound).

When to use each

How to say it

The two forms are usually unstressed and quick:

• a is normally the weak sound /ə/ (“uh”), as in a book → “uh book”. It is only said as a long “ay” /eɪ/ for emphasis: I said a book, not two.
• an is /ən/ (“uhn”); the final n links smoothly onto the next vowel: an apple sounds like “uh-napple”. That extra n exists precisely to stop two vowel sounds crashing together.

Example sentences

Common mistakes

• ❌ an university → ✅ a university. It is spelled with a vowel but said with a “yoo” (consonant) sound.
• ❌ a hour → ✅ an hour. The h is silent, so the word begins with a vowel sound.
• ❌ a apple → ✅ an apple. A real vowel sound needs an.
• ❌ a MP → ✅ an MP. You say the letter as “em”, which starts with a vowel sound.
• ❌ an European trip → ✅ a European trip. “European” starts with the “yoo” sound.
• ❌ I need an informations. → ✅ I need some information. Information is uncountable — no a/an at all.

A short conversation

A: Have you got a pen? I need to write down an address. B: Here’s a pencil. Is it an important one? A: It’s for a university interview — in about an hour!

Usage notes

• Singular countable only. A/an means “one”, so it cannot sit in front of a plural (a books ✗) or an uncountable noun (an advice ✗). For those, use some, a number, or no article.
• First mention. You often introduce something with a/an and then switch to the once it is known: I saw a cat. The cat was black.
• Jobs and descriptions. English uses a/an where some languages use nothing: She is a nurse. / He is an actor.
• Not the same as “one”. A/an is neutral; one stresses the number: I have a brother (just describing) vs I have one brother (exactly one, not two).

Compared with…

• The definite article the points to a specific, known thing, while a/an introduces a new, non-specific one: I bought a book (which one? it doesn’t matter yet) vs I read the book (we both know which). See The Definite Article ‘The’.
• Zero article (no word at all) is what you use for general plurals and uncountables: Dogs are friendly, Water is wet — never a dogs or a water. See Zero Article: When to Use No Article.

Quick recap before you practise.

Practice

Quiz

Recap cheat-sheet

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