Grammar · Nouns, articles & agreement · A1 · Beginner

A vs an

Last updated 2 September 2026

In short

Choose a or an based on the sound of the next word, not its spelling. Use an before a vowel sound (an apple, an hour, an MBA) and a before a consonant sound (a university, a one-way ticket, a European city). Silent letters and letter names are the main traps, because spelling and pronunciation disagree.

A vs an at a glance

	A	An
Rule	Before a consonant sound	Before a vowel sound
Silent 'h' words	a house, a hotel (h is pronounced)	an hour, an honest mistake (h is silent)
'U'/'eu' words	a university, a European, a uniform (start with the /j/ 'y' sound)	an umbrella, an uncle (start with a true vowel sound)
Letters and acronyms	a NATO summit ('nay-toh', consonant sound)	an MBA, an FAQ, an SOS (letter names starting with a vowel sound)
Numbers	a one-off event (starts with a 'w' sound)	an eight-year-old (starts with a true vowel sound)

Why does sound decide 'a' or 'an', not spelling?

English chooses between a and an based on the sound at the start of the next word, not the letter it happens to be written with. Use an when that sound is a vowel sound, and a when it's a consonant sound, whatever the spelling looks like.

Most of the time spelling and sound agree, so a before consonant letters and an before vowel letters feels automatic. The rule only becomes visible (and only trips learners up) in the handful of cases below, where the first letter and the first sound disagree.

She ordered an omelette for breakfast.(spelling and sound agree, vowel letter, vowel sound)
He bought a bicycle for his daughter's birthday.(consonant letter, consonant sound)

The trickiest cases: silent 'h' and words starting with 'u'

A handful of words spelled with h actually begin with a vowel sound, because the h itself is silent: hour, honest, honour, heir. These always take an, even though the first letter is a consonant.

Words that start with the letter u cause the opposite problem: many of them (university, uniform, union, useful, European) actually begin with the consonant sound /j/ ('y' as in yes), so they take a, not an, despite the vowel spelling.

It took her almost an hour to finish the assignment.(silent h → vowel sound)
He wore a uniform for his first day at the new job.('uniform' sounds like 'yoo-niform' → consonant sound)
That's an unique way to solve the problem.(→ a unique way; 'unique' starts with the /j/ sound)

Letters, acronyms and numbers

Spoken letter names follow the same sound rule. F, H, L, M, N, R, S and X are all pronounced starting with a vowel sound ('ef', 'aitch', 'el', 'em', 'en', 'ar', 'es', 'ex'), so abbreviations that begin with them take an: an FAQ, an HR manager, an SOS.

Numbers behave the same way when spoken aloud: 'one' starts with a 'w' sound, so it takes a ('a one-way ticket'), while 'eight' and 'eleven' start with true vowel sounds and take an ('an eight-year-old', 'an eleven-hour flight').

She's applying for an MBA at a university in Toronto.('M' is pronounced 'em')
It's a one-in-a-million opportunity.('one' sounds like 'won', consonant sound)
We waited for a hour and a half at the immigration desk.(→ an hour and a half)

Common mistakes with a vs an

Real learner errors, corrected and explained, the fastest way to stop repeating them.

She works for an university in Manchester.

She works for a university in Manchester.

'University' begins with the consonant sound /j/ ('yoo'), so a is correct despite the vowel spelling.

He waited for a hour before the doctor called him in.

He waited for an hour before the doctor called him in.

The h in 'hour' is silent, so the word begins with a vowel sound and needs an.

I need an USB cable for my laptop.

I need a USB cable for my laptop.

'USB' starts with the letter U, spoken 'yoo' (a consonant sound) so a is correct.

It was a honest mistake, so the teacher didn't deduct any marks.

It was an honest mistake, so the teacher didn't deduct any marks.

The h in 'honest' is silent, so the word begins with a vowel sound and needs an.

He has a MBA from a well-known business school.

He has an MBA from a well-known business school.

The letter M is pronounced 'em', which starts with a vowel sound, so an is required.

I'm looking for an one-bedroom flat near the station.

I'm looking for a one-bedroom flat near the station.

'One' starts with a 'w' sound when spoken, so a is correct despite the vowel spelling.

A vs an in IELTS

Grammatical Range and Accuracy is 25% of your Speaking and Writing scores, here is where this structure earns marks.

Speaking

Article slips like 'an university' are among the fastest-noticed accuracy errors in Part 1; examiners hear the vowel/consonant mismatch immediately, even in an otherwise fluent answer.
When you mention qualifications or job titles ('I have an MBA', 'she's a UN interpreter'), rehearse the sound aloud beforehand; abbreviations are the most common a/an trap in Part 3 discussions about work and study.

Writing

In Task 2 essays about education or technology, 'a university degree' and 'an online course' are both common phrases; check the sound of the noun immediately after a/an, not of an adjective that comes between them (an outdated system, but a useful system).
In Task 1, data commentary often needs a or an before numbers written as words ('an eighteen percent rise' vs 'a fifty percent fall'); say the number aloud to check its first sound before choosing the article.

Practise a vs an now

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Frequently asked questions

Do you use 'a' or 'an' before a word that starts with a vowel letter?

It depends on the sound, not the letter. Most vowel-letter words start with a vowel sound and take an ('an apple'), but a few, like 'university', start with a consonant sound and take a. Always say the word aloud and listen to its first sound.

Is it 'a MBA' or 'an MBA'?

An MBA; the letter M is pronounced 'em', which starts with a vowel sound. The rule follows pronunciation, so spoken letter names matter more than the written first letter.

Why do we say 'a university' if 'u' is a vowel?

Because 'university' starts with the consonant sound /j/ ('yoo'), not a true vowel sound, the a/an rule follows the sound and chooses a. The same logic applies to uniform, union, and European.

Is it 'a hour' or 'an hour'?

An hour; the h is silent, so the word actually begins with a vowel sound. Other silent-h words like honest and honour follow the same rule.

Do numbers like 'one' and 'eight' follow the same a/an rule?

Yes. 'A one-way ticket' takes a because 'one' starts with a 'w' sound, while 'an eight-hour flight' takes an because 'eight' starts with a true vowel sound. The spelling of the numeral is irrelevant; only the spoken sound counts.

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