When to use “that” or “which”

“That” and “which”: what’s the difference?

Even though “that” and “which” are frequently used in English, they are still often used incorrectly. The key to knowing when to use “that” or “which” is to understand two different clauses: defining clauses and non-defining clauses.

Write with Confidence using Editor

Elevate your writing with real-time, intelligent assistance

Learn more

What is a clause?

A clause is a group of words that contain a subject and a verb. Here are some examples of clauses:

• She smiled.
• John laughed.
• He ran.

What is a defining clause?

Defining clauses are used to give important information about someone or something. They help clarify what (or who) is being referred to. Defining clauses are usually used after the noun it describes.

“That” is used in a defining clause. For example:

• The coffee shop that closed last month was loved by the community.

Using “that” in the above sentence is necessary because it makes it clear that there are other coffee shops, but the speaker is referring to the one that is specifically closed. Without using “that,” it wouldn’t be clear which coffee shop closed or which coffee shop was loved by the community.

Here’s another example of “that” used in a sentence:

• Leather shoes that are made in Italy are typically more expensive.

In the above sentence, using “that” is important because not all leather shoes are made in Italy. Using “that” helps communicate this important information.

What is a non-defining clause?

A non-defining clause is used after a noun to provide additional information about someone or something. “Which” is used in a non-defining clause. In this case, “which” is used to convey unimportant information. The statement following “which” is not essential to comprehend what is being discussed.

Commas are used to distinguish non-defining clauses like “which” in a sentence. Here’s an example of “which” being used in a sentence:

• Her parent’s house, which is twenty minutes away, has a pool in the backyard.

In the above sentence, the house being twenty minutes away isn’t a necessary part of the sentence. The reader does not need to know how far away the house is to understand that it has a pool in the backyard.

Here’s another example of “which” being used in a sentence:

• Tyler’s favorite diner, which makes the best pancakes, is in Baltimore, Maryland.

In the above sentence, the information about the pancakes is not necessary to understand it. The sentence could still make sense without the use of the word “which”:

• Tyler’s favorite diner is in Baltimore, Maryland.

How to remember when to use “that” or “which”

The easiest way to remember when to use “that” versus “which” is to consider if the sentence uses commas. If a comma goes before and after the clause, you’ll need to use “which.” If you wouldn’t put commas before and after the clause, you’ll need to use “that.”

For example, the sentence, “Those cars, that cost $100,000, are made in Germany” would be incorrect. In this sentence, “which” must be used. The correct sentence would be, “Those cars, which cost $100,000, are made in Germany.”

If you’re not sure which word to use, remember that “which” is used in sentences with unimportant information. If you can omit the clause from a sentence and it still makes sense, use “which.” Using the example sentence above, writing “those cars are made in Germany” would still make sense. The details about the cost of the cars are simply additional information that isn’t necessary to understand the sentence.

Distinguishing between “that” or “which” can be confusing. However, these grammatical tips can help you feel more confident and better equipped in your writing, no matter if you’re brainstorming book ideas, working on an essay, or looking to improve your craft.