"A" is used before consonant sounds; "an" is used before vowel sounds. The rule depends on the SOUND, not the written letter.
Indefinite article used before words that BEGIN WITH A CONSONANT SOUND. "A cat" = consonant sound. "A university" = "u" in "university" sounds like "yu" = consonant sound. "A European" = "E" sounds like "yu". "A one-way street" = "one" sounds like "won" (w = consonant). The letter does not matter: only the SOUND matters.
She earned a university degree in economics and immediately found a job at a well-known consulting firm.
It was a one-time opportunity and she was not going to let it pass.
He described it as a historic moment — the first time the two countries had signed a peace agreement.
Indefinite article used before words that BEGIN WITH A VOWEL SOUND (a, e, i, o, u pronounced as vowels). "An apple" = vowel sound. "An hour" = "h" in "hour" is silent; the first sound is "ow" = vowel. "An MBA" = "M" is pronounced "em" = vowel. "An honest person" = "h" in "honest" is silent, sounds like "on" = vowel. The rule: SOUND, not letter.
It took her an hour to finish the report — longer than she had expected given how prepared she was.
He is an MBA graduate who worked for two major banks before starting his own company.
She made an honest mistake — nobody told her the policy had changed.
Common mistake
The two most frequent errors: (1) "an university" — INCORRECT. "University" begins with the "yu" sound (consonant), not a pure vowel. Must be "a university". (2) "a hour" — INCORRECT. The "h" in "hour" is SILENT; the first sound is "ow" (vowel). Must be "an hour". Same logic: "an honor" (silent h), "an heir" (silent h), "a hotel" (h is pronounced = consonant), "an honest" (silent h). Other traps: "a European" (sounds "yu"), "a one-way" (sounds "w"), "an FBI agent" (F sounds "ef" = vowel), "an X-ray" (X sounds "ex" = vowel).
Trick to remember it
Pronounce the word out loud (or in your mind) and listen to the FIRST SOUND. If the first sound is a PURE VOWEL (a, e, i, o, u) = AN. If the first sound is a CONSONANT (including "yu", "w", or a pronounced "h") = A. Quick test: "___ university" — say "university" out loud. Starts with "YU" (consonant) = A university. "___ hour" — say "hour" out loud. Starts with "OW" (vowel) = AN hour. The ear trick never fails if you actually pronounce the word before choosing.
Quick rule
A + initial consonant sound (including "yu" and "w"). An + initial vowel sound (including silent h). The rule is about SOUND, not spelling.
Did you know?
Before the 19th century, "an" was used before ALL words beginning with the letter H, regardless of whether the H was pronounced. "An house", "an history", "an hotel" were all correct forms. Over time, in standard British English, the H in words like "house" and "history" began to be pronounced and the rule shifted to "a house". However, in older American English and some British dialects, "an hotel" and "an historic" are still considered correct or even elegant today.
Exercise 1 · Pick the right one
She spent _____ hour trying to reach the customer service line before finally getting through.
Exercise 2 · Pick the right one
He completed _____ MBA at a top business school and joined the company as a strategy consultant.
Exercise 3 · Form the word
A + initial consonant sound (including "yu" and "w"). An + initial vowel sound (including silent h). The rule is about SOUND, not spelling.
The two most frequent errors: (1) "an university" — INCORRECT. "University" begins with the "yu" sound (consonant), not a pure vowel. Must be "a university". (2) "a hour" — INCORRECT. The "h" in "hour" is SILENT; the first sound is "ow" (vowel). Must be "an hour". Same logic: "an honor" (silent h), "an heir" (silent h), "a hotel" (h is pronounced = consonant), "an honest" (silent h). Other traps: "a European" (sounds "yu"), "a one-way" (sounds "w"), "an FBI agent" (F sounds "ef" = vowel), "an X-ray" (X sounds "ex" = vowel).
Pronounce the word out loud (or in your mind) and listen to the FIRST SOUND. If the first sound is a PURE VOWEL (a, e, i, o, u) = AN. If the first sound is a CONSONANT (including "yu", "w", or a pronounced "h") = A. Quick test: "___ university" — say "university" out loud. Starts with "YU" (consonant) = A university. "___ hour" — say "hour" out loud. Starts with "OW" (vowel) = AN hour. The ear trick never fails if you actually pronounce the word before choosing.
Bryan López
Founder of SpeakUP Academy