in half an hour vs in a half an hour

Brave Heart

Senior Member
Japan, Japanese
Hi all,

I've just come across this sentence: I'm heading home in a half an hour.

I've always understood that it should be "in half an hour", not "in a half an hour". However, when I "googled", I found there are many instances of "in a half an hour", although the number of "in half an hour" is much higher than the other. (20:1 in ratio)

So, my question is: is "in a half an hour" a correct (or acceptable) usage?

Thanks. :)
  • bibliolept

    Senior Member
    AE, Español
    "In half an hour" is more idiomatic in AE; "in a half an hour" is not nearly as common, but I suppose it is also heard in everyday conversation. On the other hand, we do say "in a quarter of an hour," so don't expect these phrases to make logical sense or to fit a rule or standard.