Difference Between Which And That

Grammar plays a vital role in effective communication, especially in writing. One common source of confusion is the proper use of “which” and “that.” These two words are often mistakenly interchanged, leading to unclear or incorrect sentences. Understanding their correct usage can greatly enhance the clarity and precision of your writing.

The main difference between “which” and “that” lies in the type of clauses they introduce. “That” is used in restrictive clauses, which are essential to the meaning of a sentence, while “which” is used in non-restrictive clauses, which provide additional, but non-essential information. Knowing this distinction is key to mastering their proper use.

When deciding between “which” and “that,” consider whether the clause in question is necessary to the sentence’s meaning. Use “that” for essential clauses and “which” for non-essential ones. By applying this rule, you can ensure your writing is both grammatically correct and easily understood by your readers.

Defining Which and That

Basic Definitions

Which and that are both relative pronouns used to introduce clauses that provide more information about a noun. The key difference lies in the type of clause they introduce. “That” introduces restrictive clauses, which are essential to the sentence’s meaning. “Which” introduces non-restrictive clauses, which provide additional, non-essential information.

Grammar Rules

Understanding when to use “which” and “that” involves recognizing whether the clause is restrictive or non-restrictive:

  • Restrictive Clauses: These clauses are essential to the meaning of the sentence. They define or limit the noun in some important way. For example: “The book that I borrowed is excellent.” The clause “that I borrowed” specifies which book is being referred to.
  • Non-restrictive Clauses: These clauses add extra information that can be removed without changing the sentence’s core meaning. They are often set off by commas. For example: “The book, which I borrowed, is excellent.” The clause “which I borrowed” adds additional information about the book but is not essential to identify it.
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Restrictive Clauses

Explanation of Restrictive Clauses

A restrictive clause is a part of the sentence that is necessary to understand the sentence’s main point. It restricts the noun to a specific subset, making the noun more specific. Without this clause, the meaning of the sentence would be incomplete or different.

Examples Using “That”

  • “The cake that she baked was delicious.”
  • “The house that is painted blue belongs to my aunt.”
  • “The dog that barks loudly lives next door.”

In each example, the clause introduced by “that” is essential to identifying the specific noun being discussed. Without the restrictive clause, the sentence would lose crucial information.

Non-restrictive Clauses

Explanation of Non-restrictive Clauses

A non-restrictive clause provides additional information about a noun that is already sufficiently identified. This information is supplementary and can be removed without altering the sentence’s fundamental meaning. Non-restrictive clauses are typically set off by commas.

Examples Using “Which”

  • “The cake, which she baked, was delicious.”
  • “The house, which is painted blue, belongs to my aunt.”
  • “The dog, which barks loudly, lives next door.”

In these examples, the clause introduced by “which” adds extra information but is not essential for identifying the noun.

Choosing the Right Word

Contextual Usage

Choosing between “which” and “that” depends on the context and the specific information you want to convey. Consider whether the clause is essential to the meaning of the sentence. If it is, use “that.” If it is additional information, use “which.”

Importance of Clarity

Using “which” and “that” correctly is important for clarity in writing. Misusing these words can lead to confusion and misinterpretation. Clear and precise writing helps convey your message effectively and professionally.

Examples and Exercises

Sentence Examples

  • “The car that is parked outside is mine.” (Restrictive)
  • “The car, which is red, is mine.” (Non-restrictive)
  • “She wore the dress that her mother made.” (Restrictive)
  • “She wore the dress, which her mother made, to the party.” (Non-restrictive)

Practice Exercises

Try rewriting the following sentences by choosing the correct relative pronoun:

  1. “The book ____ I finished last night was thrilling.”
  2. “The movie, ____ we watched together, won an award.”
  3. “The flowers ____ bloom in spring are my favorite.”
  4. “The painting, ____ he bought, was very expensive.”


  1. “The book that I finished last night was thrilling.”
  2. “The movie, which we watched together, won an award.”
  3. “The flowers that bloom in spring are my favorite.”
  4. “The painting, which he bought, was very expensive.”

Common Mistakes

Frequent Errors

  • Using “which” without commas: “The car which is parked outside is mine.” This sentence should use “that” if it’s essential information or add commas if it’s additional information.
  • Using “that” in non-restrictive clauses: “The car, that is red, is mine.” This sentence should use “which” with commas for non-essential information.
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How to Avoid Them

  • Identify the Clause Type: Determine if the clause is essential or additional information.
  • Use Commas for Non-restrictive Clauses: If the clause is non-restrictive, ensure it is set off by commas.
  • Practice and Review: Regularly practice and review sentences to reinforce correct usage.

Exceptions and Nuances

Special Cases

There are some special cases where the rules for using “which” and “that” may not be as clear-cut. These exceptions often arise from specific contexts or stylistic preferences.

  • Proper Nouns: When dealing with proper nouns, “which” is often preferred, even in restrictive clauses, for clarity. For example: “The company, which is known for its innovation, just launched a new product.”
  • Legal and Technical Writing: In legal or technical writing, the use of “which” and “that” can sometimes follow different conventions. Lawyers and technical writers might prefer “which” for both restrictive and non-restrictive clauses for precision.
  • Historical and Literary Texts: In older texts or certain literary works, you might find “which” used in ways that don’t follow modern grammar rules. For example: “The house which Jack built.”

Regional Variations

Regional differences in the use of “which” and “that” can also lead to variations in grammar rules:

  • British English: British English tends to be more flexible with “which” and “that.” It is not uncommon to see “which” used in restrictive clauses without commas. For example: “The team which won the championship celebrated late into the night.”
  • American English: American English is more rigid in its distinction between “which” and “that.” The rules we discussed earlier are more strictly followed in American English, ensuring clear separation between restrictive and non-restrictive clauses.

Impact on Writing Style

Formal vs. Informal Writing

Writing style can significantly impact your choice between “which” and “that”:

  • Formal Writing: In formal writing, such as academic papers, business reports, and official documents, adhering to strict grammar rules is essential. Using “which” and “that” correctly enhances the professionalism and clarity of your writing.
  • Informal Writing: In informal contexts, like emails to friends or casual blog posts, the rules can be relaxed. While it’s still important to be clear, the occasional misuse of “which” and “that” may not be as critical.

Reader Perception

How readers perceive your writing can be influenced by your use of “which” and “that”:

  • Professionalism: Correct usage of grammar demonstrates attention to detail and competence. This is especially important in professional and academic settings where credibility is key.
  • Clarity: Readers appreciate clear and precise writing. Misusing “which” and “that” can lead to confusion, making your message harder to understand.
  • Flow: Proper use of relative pronouns can enhance the flow of your writing, making it more enjoyable and easier to read.
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Tools and Resources

Grammar Checkers

Using grammar checkers can help ensure you are using “which” and “that” correctly. Here are some popular options:

  • Grammarly: This tool offers real-time grammar and style suggestions. It highlights incorrect usage of “which” and “that” and provides explanations for corrections.
  • Hemingway App: While primarily focused on readability, Hemingway also helps identify complex sentences and unnecessary words, indirectly aiding in proper grammar usage.
  • Microsoft Word: The built-in grammar checker in Microsoft Word is quite robust and can catch many common mistakes with relative pronouns.

Writing Guides

Consulting writing guides can further enhance your understanding and usage of “which” and “that.” Here are some recommended resources:

  • The Elements of Style by Strunk and White: This classic guide provides clear rules and examples for proper grammar usage.
  • The Chicago Manual of Style: Widely used in publishing, this manual offers detailed explanations and guidelines for various aspects of writing, including grammar.
  • Purdue OWL: The Online Writing Lab (OWL) at Purdue University offers free writing resources and instructional material. It’s a great reference for grammar rules and writing tips.


What is the main difference between “which” and “that”?

The main difference lies in the type of clauses they introduce. “That” is used for restrictive clauses, which are essential to the sentence’s meaning, while “which” is used for non-restrictive clauses, which add extra, non-essential information.

Can “which” and “that” be used interchangeably?

No, they cannot be used interchangeably. “That” should be used in restrictive clauses to provide crucial information, whereas “which” should be used in non-restrictive clauses to add supplementary details. Mixing them up can change the meaning of a sentence.

How can I decide when to use “which” or “that”?

To decide, determine if the clause is essential to the main point of the sentence. If it is, use “that.” If it adds extra information that isn’t critical to the sentence’s meaning, use “which,” and separate it with commas.

Are there exceptions to the rules for “which” and “that”?

While the general rules apply most of the time, some exceptions exist, particularly in less formal writing. However, adhering to the standard rules ensures clarity and precision, which is especially important in professional or academic writing.

Why is it important to use “which” and “that” correctly?

Using “which” and “that” correctly enhances the clarity and professionalism of your writing. It helps prevent ambiguity and ensures that your sentences convey the intended meaning without confusion.


In conclusion, understanding the difference between “which” and “that” is crucial for clear and precise writing. “That” introduces restrictive clauses essential to the sentence’s meaning, while “which” introduces non-restrictive clauses that add extra information. Mastering this distinction will improve your grammar and enhance your communication skills.

Remember to consider the necessity of the clause when choosing between “which” and “that.” This simple rule will help you use these words correctly and make your writing more effective and professional. By paying attention to these details, you can ensure that your writing is always clear and accurate.

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