A vs. An: How to Use Indefinite Articles A and An Correctly

When speaking or writing in English, you will notice that there are two forms of the indefinite article, ‘a’ and ‘an’, but which one should you use and when? In this section, we are going to be studying the two forms of the indefinite article as a way of gaining a greater understanding of their use. By the end of the section, you will be confident in choosing whether to use ‘a’ or ‘an’ in your spoken and written English.

Learn how to use indefinite articles A and An correctly in English with 13 useful grammar rules and example sentences.

A or An: Understanding the Basic 

Key Takeaways

  • Use ‘a’ before words that begin with a consonant sound. For example: a cat, a game, or a university (university starts with a ‘y’ sound, which is a consonant).
  • Use ‘an’ before words that begin with a vowel sound. For instance: an apple, an honor, an hour (honor and hour start with a silent ‘h’, thus the first sound is the vowel ‘o’).

Defining ‘A’ vs. ‘An’

The words a and an are called indefinite articles. We can use them with singular nouns to talk about any single person or thing. Deciding which indefinite article to place in front of a word depends upon the initial sound of the word, not the first letter of the word.

Using ‘A’ vs. ‘An’

When to Use “A”

A’ is used before words beginning with a consonant sound. For example:

  • A man
  • A hat
  • A lamp
  • A teacher
  • A cat
  • A book

When to Use “AN”

The article ‘an’ should be placed before words that begin with a vowel sound. The initial sound should be a, e, i, o, or u. For example:

  • An apple
  • An egg
  • An island
  • An article
  • An umbrella
  • An hour

How to Use A vs. An – Image 1

A vs. An | How to Use Indefinite Articles "A" and "An" Correctly

How to Use A vs. An – Image 2

A vs. An | How to Use Indefinite Articles "A" and "An" Correctly

A vs. An | 13 Rules for Using Indefinite Articles

Rule #1:

A’ must be used before words which begin with a vowel symbol pronounced with the same sound as the ‘y’ or a ‘w’-like sound. For example:

  • A Euro
  • A unicycle
  • A union,
  • A unique
  • A united
  • A university
  • A user
  • A unicorn

Rule #2:

Sometimes, ‘an’ is found before words beginning with the letter ‘h’.

Silent ‘h’ : ‘an’ is used before these words. For example:

  • An hour
  • An honor
  • An heir
  • An heirloom
  • An hourly
  • An honorarium
  • An honesty
  • An honorary

But this practice is going out. If ‘h’ is pronounced, ‘a’ is used:

  • A hamburger
  • A hall
  • A hat
  • A hacksaw
  • A horse
  • A house

Rule #3:

We use ‘an’ before abbreviations that begin with vowel sound. For example:

  • An M.A.
  • An M.Sc.
  • An M.B.B.S.
  • An M.L.A.
  • An N.C.C Officer
  • An M.Com.
  • An M.C.A
  • An M.B.A

Rule #4:

A or an must be used before a singular noun standing for things that can be counted. For example:

  • He was sitting in a chair.
  • She had a bottle in each hand.
  • Did you bring an umbrella?
  • I would like an apple.

Rule #4:

A or an must be used before the names of professions. For example:

  • She is a director.
  • Peter is an actor.

Rule #6:

Words like hero, genius, fool, thief, and liar take the indefinite article. For example:

  • We all regarded him as a hero.
  • I suspect he is a thief.

Rule #7:

The following word has indefinite article. Such + a/an + noun (or) Such + a/an + adjective + noun. For example:

  • Such a policy
  • Such a long trip
  • Such a great teacher
  • Such an attractive woman

Rule #8:

The following word has indefinite article. so + adjective + a/an + noun. For example:

  • So boring a book
  • So beautiful an actress

Rule #9:

Few’ and ‘Little’ are negative meaning. ‘A few’ and ‘a little’ are positive and mean ‘some‘. For example:

  • He is young and has little experience of life.
  • Sweeten the mixture with a little honey.
  • He had few coppers in his pocket.
  • I went to spend a few days at the seaside.

Rule #10:

In its original numerical sense of one. For example:

  • Not a word was said.
  • Twelve inches make a foot.
  • A bird in the hand is worth two in the bush.
  • I have a novel with an intricate plot.

Rule #11:

A an = one thing or person. For example:

  • She works in a hospital.
  • There’s a problem with the drains.
  • I’ve got a puppy.
  • There was a girl sitting next to him.

Rule #12:

We use a an when we say what a thing or a person is. For example:

  • “Coca Cola” is a beverage.
  • Badminton is an indoor game.
  • A dog is a domestic animal.
  • Mary is a shy girl.

Rule #13:

We use a an for jobs, etc. For example:

  • She works as a nurse in a hospital.
  • John is a fireman.
  • I want to be a doctor.
  • She is a cashier in a bank.

Note: The indefinite articles are not used before plural nouns, proper nouns, abstract nouns, uncountable and material nouns. For example:

  • A dog is a faithful animal.
  • Dogs are faithful animals.

Rules for Using Articles A vs. An – Image 3

rules for using a vs. an

A or An: Examples in Sentences

Examples of “A” in Sentences

  1. She adopted a dog from the shelter.
  2. He is a university professor.
  3. It’s a one-time offer.
  4. She took a European vacation last summer.
  5. I saw a unicorn in my dream.

Examples of “An” in Sentences

  1. She ate an apple for lunch.
  2. It was an honor to meet the author.
  3. He has an MBA from Harvard.
  4. They found an old coin in the garden.
  5. I need an hour to finish this task.

Exercises to Learn the Difference

Determine if the usage of “a” or “an” is correct.

  1. She has a unique perspective on the matter. (True/False)
  2. It’s an honor to meet you. (True/False)
  3. He is a honest man. (True/False)
  4. I need an umbrella because it’s raining. (True/False)
  5. That’s an interesting idea. (True/False)
  6. I saw a elephant at the zoo. (True/False)
  7. She made an mistake in the calculation. (True/False)
  8. It takes a hour to get there by train. (True/False)
  9. He gave me a apple from his garden. (True/False)
  10. It was an historic event for the company. (True/False)


  1. True
  2. True
  3. False (Correct usage: “an honest man”)
  4. True
  5. True
  6. False (Correct usage: “an elephant”)
  7. False (Correct usage: “a mistake”)
  8. False (Correct usage: “an hour”)
  9. False (Correct usage: “an apple”)
  10. True (Note: Both “a historic” and “an historic” are used, depending on whether the “h” is pronounced or not. “An” is often used when the “h” is silent, but “a” is used when the “h” is pronounced.)

Frequently Asked Questions

Is it “a unicorn” or “an unicorn”? We use “a” before words where the initial sound is a consonant or consonant-like sound. Even though “unicorn” starts with a vowel, the first sound is “yoo,” which is a consonant sound, so it’s “a unicorn.”

Do we say “a one-time” or “an one-time”? It might be tricky because “one” starts with ‘o’, a vowel. But as “one” starts with the “w” sound, we say “a one-time” event.

Why do we use “an” before “honor” but “a” before “hotel”? Words beginning with ‘h’ can be pronounced differently. If the ‘h’ is silent and the word starts with a vowel sound, like “honor,” we use “an.” If the ‘h’ is pronounced, like in “hotel,” we use “a.”

Are abbreviations treated differently? Yes, with abbreviations, we pay attention to the sound of the first letter when it’s read aloud. For example, “an MBA” (em-bee-ay) because it starts with a vowel sound, and “a NASA project” (en-ay-ess-ay) because it starts with a consonant sound.

  • Is it “a user” or “an user”?
    • We say “a user” because the ‘u’ in “user” makes a ‘yoo’ sound, similar to “a unicorn.”
  • What about words that start with ‘eu’?
    • Typically, words that start with ‘eu’ tend to have a ‘yoo’ sound, so we use “a,” like in “a eulogy.”

Make a note that it’s the sound and not the first letter of the word that’s important when deciding to use “a” or “an”!

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