Using “a” and “an” Before Words

By Daniel Scocco

Raphael asks: When should I use “a” and when should I use “an” before the different words? For example, should I say “a hour” or “an hour?” I stumble over this everytime and dont’t know if I’m getting it right, as I’m not speaking and writing English natively.

The Rule

The rule states that “a” should be used before words that begin with consonants (e.g., b, c ,d) while “an” should be used before words that begin with vowels (e.g., a,e,i). Notice, however, that the usage is determined by the pronunciation and not by the spelling, as many people wrongly assume.

You should say, therefore, “an hour” (because hour begins with a vowel sound) and “a history” (because history begins with a consonant sound).

Similarly you should say “a union” even if union begins with a “u.” That is because the pronunciation begins with “yu”, which is a consonant sound.


Deciding which version you should use with abbreviations is the tricky part. First of all you need to understand if the abbreviation is pronounced as a single word or letter by letter.

While we say “a light-water reactor,” the abbreviation is “an LWR.”

Similarly, you should use “an NBC reporter” (because “NBC” is pronounced “enbisi”) and “a NATO authority” (because “NATO” begins with a “ne” sound).

81 Responses to “Using “a” and “an” Before Words”

  • Ken Sousa

    Thanks for providing the rules around the use of the articles “a” and “an”. I am continually appalled when I hear people who are supposed to be professionals in the use of the language, like news anchors, use “a” in front of everything, regardless of the starting sound of the following noun. For shame! Perhaps a little stronger English program in some of our major universities is in order.

  • Maliha Mahmood

    If you are a teacher and have to explain the background of “a” & “an” usage before “h” words, best you can do is to write the words that have “o” after “h”.
    These words have letter or quarter vowel “h” in the beginning .staying silent and letting the vowel followed says it’s name . But it’s just for few words.
    In American English even “herb” will be written as an herb

  • John

    How does the a and an take place as in “a Hispanic” or an Hispanic

  • Jerry

    I feel we got it correct. We go by the following pronunciation. I have been speaking English since I was 3 or 4 and I find there is always something new to learn. What a problem for non-native speakers.

    For each word you have to learn the spelling, pronunciation, and usagel of each words. There really are no pronunciation rules or spelling rules that are consistent.

    I was in Italy and the guide pronunced laser as lass-er. I helped him, but he was so confused. Thus we can have spelling bees in our language. Not so in Spanish or Korean where all letters are pronunced. No spelling bees there!

  • din

    that’s the same with UFO- like an UFO
    That’s also the same with NBL- like “an NBL”

  • kapp


    It depends on your corporate culture. During discussions with peers, do you simply use the initialism (saying S.R.) or do you say the entire thing (saying “Service Request”).

    If the former, it will be “an SR”, since you are pronouncing the “S” letter, as “Ehs”, which begins with a vowel sound.

    If the latter, the phrase begins with “Service”; the “S” sound in the word is a consonant, so you would write “a SR”.

    Since people will read the written as they usually speak the verbal, use the one that coincides with how most would read it.

  • Najam

    We in our company use abbreviation “SR” for “Service Request”. Should I use an SR or a SR?

  • Damen Stephens

    It seems long-winded and confusing to explain the rule in such a manner:

    “The rule states that “a” should be used before words that begin with consonants (e.g., b, c ,d) while “an” should be used before words that begin with vowels (e.g., a,e,i). Notice, however, that the usage is determined by the pronunciation and not by the spelling, as many people wrongly assume.”

    Would it not be easier to state that:

    “‘a’ should be used before a consonant sound, whereas ‘an’ should be used before words which begin with a vowel sound”.

    There is then no need to distinguish between pronunciation, spelling and people’s incorrect assumptions.

  • Sharon

    Thank you so much for this post! My daughter is 8 and was struggling with a/an. I was having difficulty explaining it to her, and your blog here did just the trick! I too have seen many misuses of the words a and an. It drives me crazy to see because it just doesn’t sound right. Hopefully more people will see this.

  • Peter

    @Aimee: yes, change it to “an”

  • Aimee


    Sometimes, we say statements like this,
    “Hey, don’t you think Will Smith is doing a Sylvester Stallone here?”

    If we use a name starting with a vowel, will the ‘a’ change to ‘an’?

    For example: Will it be correct like this?

    “Hey, don’t you think Will Smith is doing a Arka Saha here?” Or will it change to ‘an’??

    Genuine doubt.

  • Talal

    Thanks for clarifing this in the best possible way. Keep up the good work.

  • John

    Thank you for this clarification. I recall the proper usage of “a” and “an” from Catholic grammar school but of late I have noticed some public figures INCORRECTLY using an “a” when an “an” would be proper. Most notably of late …Dr. Oz on his TV show. There are quite a few others ( newscasters, actors on TV) also, but I can’t bring to mind their names. To me, it was, and is, a culture shock.

  • Xyciana

    If you do get really stuck, I use Msoft Word and that seems to get it right every time in its spell check. Other word processing products may also do the same.

  • Paul Justice

    This is a great post, I always considered my grammar good, but when I write a different matter. Thanks for this article, it will greatly help my writing.

  • steve

    I am from London and I was always taught to pronounce my h’s so I say hotel and the h is not silent where others say ‘otel, I accept the rule but does it mean different dialect and accent will have different ideas about using a or an?

  • Akhilesh

    A alphabet or an alphabet ?

    The letter “I” is a alphabet, or the letter “I” is an alphabet. ?

  • Valder

    I think there is a typo in here:
    “While we say “a light-water reactor,” the abbreviation is “an LWR.””

    It should be “a LWR”.

  • Jennifer

    an HMO? or a HMO? I thought I knew this, it sounds like it should be an HMO to me but the doc I am proofing says a HMO!

  • yes

    what if, it is followed by numbers?? (i.e 123, 4, 786 etc)

  • Vijay

    Good Post…:-)

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