When To Use An or A

Have you ever wondered when to use an or a? It’s all about the sound. If the word begins with a vowel sound, you use ‘an.’ If it begins with a consonant sound, use ‘a.’

Indefinite articles can be tricky when writing, especially for non-native speakers, but their use is easy to master. You only need to listen.

What Are Articles?

In grammar, articles are the little words that define a noun, making it either specific or unspecific. There are three articles in the English language: ‘the,’ ‘an’ and ‘a.’

‘The’ is a definite article that’s used for specific things. ‘A’ and ‘an’ are indefinite articles, which means they describe things we don’t know yet.

  • The cat is sitting by the window.
  • I have a cat.
  • I ate an apple.

In the first example, we know the cat and can probably see it. The second one has a cat we’re referring to for the first time, so it’s not yet known in the conversation. The third one refers to an unspecified apple.

When to Use An or A? inforgraphic image

How to Pick the Right Indefinite Article

With indefinite articles, you have two options, but you’ll need a bit more to know when to use ‘an’ or ‘a’.

The basic rule for picking between them is that ‘a’ goes before nouns—or adjectives preceding nouns—that begin with a consonant. ‘An’ is used with words starting with a vowel.

  • An apple fell off a tree.
  • A dog and an octopus.
  • A warm sweater vs. an affordable dress.

Sounds pretty easy, right? Well, like with most things in grammar, there are exceptions to the basic rule.

Consonants That Sound Like Vowels

When a consonant, usually an ‘h’, sounds like a vowel or isn’t pronounced, you’ll need to use ‘an’. The same letter may behave in different ways with different words.

  • An hour vs. a home.
  • An honorable mention vs. a horrible situation.

‘Hour’ and ‘honorable’ begin with a silent ‘h’, while ‘home’ and ‘horrible’ have a pronounced consonant.

Vowels Pronounced as Consonants

This goes the other way, too. When a vowel sounds like a consonant it goes with ‘a’.

  • A eulogy vs. an epic.
  • A European vs. an Egyptian.
  • A unique solution vs. an understandable problem.
  • A one-dollar bill vs. an obedient person.

‘Unique’, ‘eulogy’, ‘European’ start with a hard consonant sound like the word ‘you’, so they require ‘a’ as the article even if they begin with vowels. ‘One’ has a hard ‘w’ sound, even if it’s written with a vowel.


To further complicate things, acronyms are given the article according to how they sound like when they’re pronounced, not always the letter they start with.

  • An FBI agent vs. a CIA agent.
  • An EU country vs. a UN member.
  • An ROI vs. a URL.

FBI is pronounced with an ‘ef’, so it requires the article that goes with a vowel sound. UN and URL have a hard ‘y’ sound in the beginning, so they’re accompanied by ‘a’.

Acronyms like NATO or NASA can be tricky. They’re pronounced not by spelling out the letters but by reading the word straight out. In these cases, simply use the article of the sound they begin with.

  • A NASA satellite.
  • A NATO decision.

A History Or an History?

Some words can carry either ‘an’ or ‘a’ as the article. This happens with some words that start with ‘h’, like history and hotel.

While it’s no longer common, but you can find ‘an history’ or ‘an hotel’ in older texts and it’s not incorrect. This may be because these words used to be pronounced more like their French translations, with a silent ‘h’.

A Herb Or an Herb?

Some cases depend on the country. A herb in British English is an herb on the other side of the Atlantic. It may look confusing, but it’s easy to master when you think about pronunciation.

Since Americans don’t pronounce the ‘h’, the word uses ‘an’. Brits do include the consonant in the beginning, so the word goes with ‘a’.

Either way, you’ll probably be understood.

Bottom Line

Feeling lost? Don’t worry. This may all seem pretty confusing, but it’s definitely easier than it looks.

Here’s a tip: always read your writing out loud. It will help you detect errors and you’ll hear when to use ‘an’ or ‘a’.

If the word begins with a vowel sound, you’ll notice you need something to separate it from the article. ‘A apple’ is hard to pronounce without the words jumbling together. ‘An dog’ is clunky and hard to say out loud.


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