Take the 2-minute tour ×
English Language & Usage Stack Exchange is a question and answer site for linguists, etymologists, and serious English language enthusiasts. It's 100% free, no registration required.

Most of the time one or the other feels better, but every so often, "which" vs. "what" trips me up.

So, what's the exact difference and when should you use one or the other?

share|improve this question

2 Answers 2

up vote 29 down vote accepted

"Which" is more formal when asking a question that requires a choice between a number of items. You can use "What" if you want, though.

Generally speaking, you can replace the usage of "which" with "what" and be OK grammatically. It doesn't always work the other way around, however. There needs to be a context of choice. For example:

Which/What flavor of ice cream do you want?

  • Either is fine, but "which" is better.

Which/What do you want for dessert?

  • "Which" only works in the context of being presented with choices (e.g. a dessert cart right in front of you).
share|improve this answer

Questions of attribute which and what: We usually use which when we are asking about a fixed or limited number of things or people, and what when we are not. Often, however, we can use either which or what with little difference in meaning. Compare:

  • What towns do we go through on the way?

    The speaker doesn't know the area.

  • Which towns do we go through on the way?

    The speaker knows the area and the towns in it.

If you mean when they are conjunctions, it is another question.

share|improve this answer
    
So the answer is that ultimately there are cases where there are no rules but you have to kinda know the connotations? Huh. –  Christian Jun 28 '13 at 16:32
    
"Which are winter months in Europe?" or "What are winter months in Europe"? –  Peter May 26 at 11:32

protected by RegDwigнt May 20 '12 at 10:11

Thank you for your interest in this question. Because it has attracted low-quality answers, posting an answer now requires 10 reputation on this site.

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.