• 2-minute read
  • 26th November 2018

Word Choice: “What” and “Which” in Questions

“What” and “which” are both used for asking questions. They can even be used interchangeably in many cases. However, they’re not always interchangeable. So check out our guide to using “what” and “which” in questions to make sure your writing is always error free.

“What” and “Which” in Questions

“What” and “which” are both interrogative pronouns. In other words, we can use “what” and “which” in questions when we want someone to specify something. For example:

What TV shows do you watch?

Which TV shows do you watch?

Here, we’re asking someone to specify the TV programs they enjoy. We can use either “what” or “which” in this case because there is a large but not unlimited number of potential answers.

Open Questions vs. A Limited Range of Answers

The difference between “what” and “which” emerges when we’re dealing with questions that are either very open or fairly limited. When a question is very broad, we use “what”:

What shall we do today?

Which shall we do today?

Here, “which” is not grammatically incorrect. But it does imply a limited range of choices (e.g., as if the conversation were about either going to the beach or going to the movies). “What,” on the other hand, leaves the question open to any number of possible answers.

But we can reverse this by asking a question with a limited range of choices:

What hand do you write with?

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Which hand do you write with?

In this case, “which” is correct because the answer has to be either “left” or “right.” We also use “which” before “of” and “one,” as these imply a limited set of possible answers:

Which of my hats do you like most?

Which one should I wear?

Here, using “which” suggests a limited number of hats from which to choose.

Summary: What or Which?

You can use both “what” and “which” in questions when asking for information that specifies something. Generally, when a question is open to many answers, it is better to use “what”:

What shall we do today?

But when there are a limited number of choices, use “which”:

Which hand do you write with?

If you’d like help getting “which” and “what” in order, just let us know.

Comments (8)
31st July 2021 at 19:09
Hi !. A question... When we say.. what is the difference...or which is the difference... it is doesn´t clear for me... Please Can you explain me?
    2nd August 2021 at 11:15
    Hi, John. This would depend on the context to some extent, but I suspect your question relates to the "Open Questions vs. A Limited Range of Answers" section of the post. In short, you would only use "which" if you were referring to a specific set of differences (e.g., "The car is a different colour and size to your old one. Which difference do you like most?" would be correct since we're asking someone to choose between two specific differences), whereas you'd use "what" for an open question (e.g., "What are the differences between this car and that car?" implies that we're asking an open question rather than inquiring about specific differences).
    31st May 2023 at 15:55
    Much more Educative
      4th June 2023 at 10:47
      Thanks, Joseph! Really glad you found this helpful.
Puis Ntomakeh
18th January 2023 at 13:47
Please which of these two sentences is correct? Your contract "which" started with us last year... Your contract "that" started with us last year...
    25th January 2023 at 12:56
    Hi, Puis. From your example, it looks like this is a relative statement. Without the full sentence and context, it’s difficult to tell which of these might be correct, but you will probably find our article here helpful - https://proofed.com/writing-tips/word-choice-that-vs-which/
12th May 2023 at 19:46
If “what” is used for broad questions,then why do we use it in a question like “what is your name”?
    21st May 2023 at 14:20
    Hi, Jordan. “What” is used in this case as there is a very broad range of answers; the person asking the question doesn’t know which out of the many possible names the other person would have. When the possible answers are more limited, then “which” is used. A good example for explaining when to use “which” is the right hand or left hand one in our article above, or, to take your example, if the other person could be called either Susan or Susie, the questioner would ask “Which name do you prefer?”

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