Word Choice: When to Use ‘An’ Instead of ‘A’

On one level, the indefinite articles (‘a’ and ‘an’) are two of the simplest words in the English language. In all likelihood you use them hundreds of times every day without even thinking about it. They’re also essential to constructing grammatical sentences. Despite this, here at Proofed, we often see confusion about how ‘a’ and ‘an’ should be used.

Most of the time, the question of which to use in any given situation is fairly straightforward, but in English every rule has its exceptions. In this case, the exceptions even trip up native speakers from time to time. But mastering how to use these two little words correctly is essential if you want your writing to be clear, easy to follow and professional.

The General Rule: ‘A’ and ‘An’

The two versions of the indefinite article in English are necessary because although ‘a’ suffices for words which begin with consonants, it’s less useful when it comes before a word which starts with a vowel. Using ‘an’ separates the article from the following word, making it easier to pronounce. Consider the following example and you’ll see why:

A chicken and an egg. – Correct

An chicken and a egg. – Incorrect

You will, therefore, generally need to use ‘a’ before words beginning with consonants and ‘an’ before words beginning with vowels. But this is where things get tricky…

The Exceptions: Vowels Which Sound Like Consonants

The first important exception is when a word sounds like it starts with a vowel but doesn’t, such as ‘university’ (pronounced ‘yoo-niversity’ rather than ‘oo-niversity’). Words which start with consonant sounds always take ‘a’ rather than ‘an’:

Hannah took shelter under a eucalyptus tree. – Correct

Hannah took shelter under an eucalyptus tree. – Incorrect

The Exceptions: The Silent ‘H’

You also have to be careful about words which start with a silent ‘h’, such as ‘heir’ and ‘honest’. Since these sound like they begin with a vowel (e.g. ‘heir’ is pronounced like ‘air’, and ‘honest’ is pronounced ‘on-est’) they should be preceded by ‘an’ rather than ‘a’:

Tom searched far and wide to find an honest man. – Correct

Tom searched far and wide to find a honest man. – Incorrect

‘A’ or ‘An’?

The key to knowing which indefinite article to use lies in the sound a word makes when spoken out loud:

• If a word starts with a consonant sound, it should be preceded by ‘a’ regardless of how it is spelled (e.g. ‘a European’ or ‘a one-man band’).
• If a word starts with a vowel sound, even if preceded by a silent ‘h’, use ‘an’ (e.g. ‘an hour’ or ‘an honour’).

You should now have a better idea of when to use ‘a’ and ‘an’ in your writing. But if indefinite articles are still giving you problems, you might want to give Proofed’s 500-word free sample service a try!