A hour or an hour: which is correct?
The correct form is "an hour". The choice between a and an depends on the sound, not the letter: the h in hour is silent, so the word starts with a vowel sound ("our"), and vowel sounds take an.
The rule
Use an before a vowel sound and a before a consonant sound. That's why we say an hour but a house, and a university (it starts with a "you" sound) but an umbrella.
| Silent h: use "an" | Spoken h: use "a" |
|---|---|
| an hour, an hourly rate | a half hour, a house |
| an honest mistake, an honor | a holiday, a hotel |
| an heir, an heirloom | a hero, a horse |
"A historic" or "an historic"?
In modern American and British English, "a historic" is standard because the h is pronounced. "An historic" is an older style still used by some speakers who soften the h.
Half an hour or a half hour?
Both are correct: half an hour is more common in British English, a half hour in American English. Need one? Start a 30-minute timer.
How to spell and say "hour"
Hour is spelled h-o-u-r and pronounced exactly like "our" (/aʊər/ or /aʊr/); the h is silent. The plural is hours, said like "ours". An hour is 60 minutes, or 3,600 seconds; how a second is defined explains where that length comes from. In time phrases, hours also means set working or opening times ("office hours", "after hours").
Questions people ask
Is it "a hour" or "an hour"?
"An hour." The h is silent, so the word begins with a vowel sound.
Is it "an hourly" or "a hourly"?
"An hourly", for the same reason: "an hourly wage".
Why is it "a university" but "an hour"?
Because the article follows the first sound. University starts with a "you" (consonant) sound; hour starts with an "ow" (vowel) sound.
Sources
Related: words and idioms about time · "clock it" meaning · what is time?
Last updated October 21, 2026.