That or Which?

The usage of that or which can confuse the best of writers, and often leaves the grammarians scratching their heads. Below we will look at both words and try to find a solution.

That can be used as a demonstrative pronoun, an adjective, a conjunction and sometimes as an adverb. But the most confused use of that occurs when the writer is not sure if they should use that or which.

That is often omitted when it is used to introduce a noun clause or after a verb that expresses a process.


The book that he read was Oliver Twist.

The book he read was Oliver Twist.

The second example reads fine without the that. This is quite common in modern writing and is in line with The Elements of Style: A Style Guide for Writers* ‘omit needless words’ mantra.

That is also used after a restrictive clause; meaning that it restricts the clause that it follows so no confusion is made.


He picked up the books that were on the bedroom floor.

In this example that restricts the books being referred to and serves to avoid confusion as to which books are being picked up.

Which can be used to introduce direct or indirect questions, as well as in relative clauses.

Which is usually preferred after a non-restrictive clause; meaning the information after which does not have to refer directly to the clause it follows as it is only adding extra information.


He got the job, which lead to his improved finances.

In this example which is only adding some extra information, it is not restrictive in that it is not referring directly to him getting the job.

It’s no wonder we get confused with these two words, especially when it is possible to sometimes swap the two. Which can also be used in place of that in a relative clause, though this is usually as a style choice.

To try and keep their usage straight in your mind, remember the following:

That is used to clarify. Which is used to add extra information.

(* Strunk – The Elements of Style: A Style Guide for Writers)

Kristy Taylor is a syndicated freelance journalist with articles and short stories strewn across all forms of media. She has written and published numerous books, and is the executive editor of KT Publishing, which encompasses several web sites. For free listings of short story competitions visit

To contact Kristy, email her at

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