Which Vs That: A Comprehensive Guide

For many writers, knowing the difference between which vs that can really trip them up. This guide will help set the record straight. 

The words “that” and “which” are problematic for English writers because they carry similar meanings. Yet strong writers will know when to use each of these words, and how to use commas appropriately with them, to make the meaning of the sentence clear.

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Which vs That: Similar but Different

Which vs That

Both that and which are relative pronouns. The Cambridge Dictionary defines relative pronouns as pronouns that introduce relative clauses. A relative clause is a dependent phrase with a subject and verb that cannot stand alone.

Both of these terms tell the reader to look closely at the information provided. They indicate additional information that gives a better meaning to another part of the sentence. These could be called, “defining clauses” because they define another part of the sentence.

In addition, these words can get used as adjectives, pronouns, conjunctions or adverbs. However, the most common use is as a relative pronoun.

These words are easy to confuse because they look similar in the sentence structure, but a closer look at the grammar shows they are not the same.

Restrictive vs Non-Restrictive Phrases

The key to understanding how to use “that” and “which” appropriately is understanding the difference between restrictive and non-restrictive clauses.This type of clause is necessary for the meaning of the sentence to be accurate.

This is an example of a sentence with a restrictive clause:

  • The mom’s necklace that was made from macaroni noodles was a treasured keepsake.

In this sentence, the information about the necklace being made from macaroni is vital to the meaning of the sentence. It tells the reader that the mom’s child made the necklace, which is why it was a treasured keepsake. This makes it restrictive.

A nonrestrictive clause does not add meaning and is not necessary for the sentence. This would include:

  • The mom’s necklace, which matched her blue dress, was a treasured keepsake.

In this sentence, the color of the necklace and dress is not vital to understanding the sentence’s meaning, and thus the phrase is non-restrictive.

Use “That” for Restrictive Clauses

English writers should use “that” when writing clauses that are restrictive. The use of “that” indicates the information in the clause is needed to understand the noun, or antecedent, that comes before. Here are some examples:

  • My dog that I adore ate my shoe.
  • The cashier that sold me the dress said it was returnable.
  • The sweater that my mother gave me on my birthday got torn.

In the first example, the information about adoring the dog makes the sentence mean more, because it shows that the writer is not going to be too angry. In the second, knowing it was the same cashier that sold the dress giving the information about returns is important.

Finally, in the sweater example, the information differentiates between the writer’s other sweaters.

Use “Which” for Non-Restrictive Clauses

On the other hand, “which” is the term used for a non-restrictive relative clause. If the clause is not fully necessary to make the meaning of the sentence clear, it is set off by a comma and “which.” Here are some examples:

  • We were late because of my daughter’s nap, which is fine because she needed it.
  • The car, which parked next to me, was a brilliant red shade.
  • The cloud made the child cry, which surprised the boy’s mother.

In each of these, the main meaning of the sentence does not change with the addition of the clause, so “which” is the appropriate pronoun.

The Comma Trick

Which vs That
When presenting extra information with “which” in a nonrestrictive clause, you do set the clause off with commas

Commas can help you when it comes to “which” and “that.” If you are using “that” and presenting important information in a restrictive clause, then you do not set off the clause with commas.

However, when presenting extra information with “which” in a nonrestrictive clause, you do set the clause off with commas. This shows that the clause is not vital to the rest of the sentence.

Sometimes the clause could even be a second sentence separate from the original one.

The Final Word on Which vs That

Because they are both relative pronouns that set off clauses, “that” and “which” can trip up writers. To choose the right word, always determine if the clause is necessary to the meaning of the sentence, in which case you use “that” and no commas. If it is not, then you use “which” with commas.

It really is that simple to learn the difference between which vs that.

FAQs About Which vs That

What is the grammar rule for which vs that?

If the clause is defining or restrictive, meaning that it gives essential information to the meaning of the sentence use “that.” If the clause is non-defining or nonrestrictive, which means it does not change the sentence's meaning, use “which” and commas.

Are “which” and “that” interchangeable in the English language?

No, even though they are both pronouns that have a similar role in the sentence, they aren’t interchangeable according to grammarians. Only use “that” with restrictive clauses and “which” with nonrestrictive.

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  • Nicole Harms has been writing professionally since 2006. She specializes in education content and real estate writing but enjoys a wide gamut of topics. Her goal is to connect with the reader in an engaging, but informative way. Her work has been featured on USA Today, and she ghostwrites for many high-profile companies. As a former teacher, she is passionate about both research and grammar, giving her clients the quality they demand in today's online marketing world.

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