Commas before or after “Which” with examples in sentences

Commas, the unsung heroes of sentence structure, play a crucial role in conveying meaning effectively when it comes to the placement of commas before or after “which,” understanding the rules is vital for clear and coherent communication.

Comma Before “Which” in Sentences

In many instances, a comma is placed before “which” to set off non-restrictive clauses. This technique adds extra information to a sentence without altering its fundamental meaning. 

In non-restrictive clauses, where the information is supplementary and not crucial to the sentence’s core meaning, a comma is placed before “which.”

Restrictive Clauses are essential to the sentence’s meaning and do not have a preceding comma.

Non-restrictive clauses provide extra information and are set off by commas.

Example 1:

1. The novel, which was written in the 19th century, remains a classic. (Non-restrictive clauses)

Here, the clause “which was written in the 19th century” provides additional information but is not essential to understanding the main point of the sentence.

Example 2:

2. The concert, which took place last night, was a mesmerizing experience.  (Non-restrictive clauses)

Here, the clause “which took place last night” is additional information that can be omitted without altering the essential meaning.

Example 3:

3. My laptop, which is brand new, crashed unexpectedly.  (Non-restrictive clauses)

Here, the non-restrictive clause “which is brand new” adds information but is not crucial to understanding why the laptop crashed.

Example 4:

4. The student, who had studied diligently, aced the exam.  (Non-restrictive clauses)

The non-restrictive clause “who had studied diligently” adds context without changing the core meaning of the sentence.

Avoiding Common Pitfalls

One common mistake is erroneously placing a comma before “which” in a restrictive clause, leading to confusion.

Example 5:

5. The book, that I borrowed last week, is on the shelf. (Restrictive Clauses)

This sentence introduces confusion as the restrictive clause “that I borrowed last week” should not have a preceding comma.

Example 6:

6. The car that requires immediate attention is in the garage. (Restrictive Clauses)

In this case, the clause “that requires immediate attention” is restrictive, specifying which car needs immediate attention.

Comma After “Which” in Sentences Usage with Examples

Commas often considered the unsung heroes of punctuation, play a pivotal role in shaping the flow and clarity of written language. 

When dealing with the word “which,” knowing when to use a comma after it is essential for constructing sentences that are both grammatically correct and easily understood.

We will unravel the rules and guidelines governing the placement of commas after “which,” accompanied by illustrative examples to enhance comprehension.

The Core Rule

In sentences featuring non-restrictive or parenthetical clauses introduced by “which,” a comma is appropriately placed after the word.


1. She adopted a new dog, which, incidentally, was a rescue.

Here, the clause “which, incidentally, was a rescue” adds extra information without altering the core meaning of the sentence.

Non-restrictive clauses and Commas

Non-restrictive clauses, providing additional information that is not integral to the main clause, are typically set off by commas.


1. The garden, which was meticulously tended, thrived throughout the seasons.

In this instance, the non-restrictive clause “which was meticulously tended” enhances the description of the garden but is not necessary for understanding the central message.

Ensuring Clarity in Complex Sentences

In more complex sentence structures, the placement of a comma after “which” aids in distinguishing between different elements.


1. He embarked on a journey, which, unbeknownst to him, would change his life forever.

Here, the commas surrounding “which” set apart the parenthetical phrase “unbeknownst to him,” contributing to a clearer understanding of the sentence.

Avoiding Commas in Restrictive Clauses

It is important to note that in restrictive clauses, where the information is crucial to the sentence’s meaning, a comma after “which” is omitted.


1. The manuscript which details the historical events is on the shelf.

In this case, the clause “which details the historical events” is restrictive, and no comma is used as the information is integral to the sentence.

Enhancing Readability and Emphasis

The strategic use of commas after “which” not only contributes to readability but also emphasizes the additional information provided by the clause.


1. The antique shop showcased rare artifacts, which, surprisingly, were still in pristine condition.

Here, the comma after “which” draws attention to the surprising nature of the information within the non-restrictive clause.

Guidelines for Using Commas with “Which”

Commas play a crucial role in guiding the flow and structure of sentences, particularly when the word “which” is involved. Here are succinct guidelines to help you master the art of using commas with “which” effectively:

  1. Use a comma before and after “which” when introducing non-restrictive clauses.
  2. Employ commas to separate items when “which” is part of a list.
  3. When non-restrictive clauses are part of a list, use commas to set them off.
  4. Use commas to set off parenthetical phrases introduced by “which.”
  5. Separate clauses with commas when “which” introduces a new thought in complex sentences.
  6. Introduce a comma after “which” for emphasis or to enhance clarity in longer sentences.
  7. Omit commas after “which” in restrictive clauses to maintain sentence integrity.
  1. Example 1: The garden, which was meticulously tended, thrived.
  2. Example 2: The project included research, which analyzed data, development, which created new features, and testing, which ensured quality.
  3. Example 3: The team tackled design challenges, which required creativity, and technical issues, which demanded expertise.
  4. Example 4: The experiment yielded unexpected results, which, surprisingly, delighted the researchers.
  5. Example 5: She presented the findings, which astonished the audience, and then answered questions.
  6. Example 6: The proposal outlined various initiatives, which, without a doubt, would reshape the industry.
  7. Example 7: The document which outlines the project requirements is on my desk.

By following these guidelines, you’ll wield commas with precision, ensuring your writing remains clear, concise, and grammatically sound. 

Common Mistakes to Avoid

One common mistake is placing a comma before “which” in a restrictive clause, leading to confusion. It’s essential to carefully analyze the role of the clause in the sentence to determine the appropriate comma placement.

Comma Usage for Restrictive Clauses

When dealing with restrictive clauses, which provide necessary information, omitting the comma is key. This ensures that the sentence maintains its intended meaning without unnecessary pauses.

No Commas in Restrictive Clauses:

In restrictive clauses, which are essential to the sentence’s meaning, commas should not be used. The information in these clauses is necessary for understanding the noun it modifies.


1. The book that I borrowed last week is on the shelf.

In this sentence, “that I borrowed last week” is a restrictive clause providing crucial information about the book.

Comma Usage for Non-Restrictive Clauses

Non-restrictive clauses, on the other hand, offer additional information that, while interesting, doesn’t alter the sentence’s core meaning. These clauses are set off by commas, as seen in the earlier example of a classic novel.

  1. Commas Set Off Non-Restrictive Clauses:
  2. Additional Information Without Commas is Restrictive:
  3. Non-Restrictive Clauses in the Middle of Sentences:
  4. Appositives and Non-Restrictive Clauses:


1. My friend, who lives in Paris, is visiting next month.

The non-restrictive clause “who lives in Paris” adds extra information but is not necessary for understanding the sentence.

2. My sister who lives in London is visiting next month.

Without commas, the clause “who lives in London” becomes restrictive, implying there is more than one sister.

3. The mountain, which is known for its breathtaking views, is a popular hiking destination.

The non-restrictive clause “which is known for its breathtaking views” is enclosed by commas.

4. My favorite novel, which won numerous awards, is on the shelf.

The non-restrictive clause “which won numerous awards” acts as additional information about the novel.

Impact of Commas on Sentence Clarity

Commas contribute significantly to sentence clarity. They guide readers through the intended meaning, preventing misunderstandings. Proper placement enhances the flow of information, allowing for smooth and coherent comprehension.

Consider this example:

1. The professor, who specializes in linguistics, presented an intriguing lecture.

Here, the non-restrictive clause “who specializes in linguistics” adds context without changing the essential meaning of the sentence.

Comma Placement in Complex Sentences

In complex sentences, knowing where to place commas can be challenging. However, a general rule is to use commas to separate independent clauses when “which” introduces a new thought.

Independent Clauses with Coordinating Conjunction:

1. She decided to pursue a Ph.D., and, to her surprise, she was admitted to the prestigious program.

In this example, the comma separates two independent clauses connected by the coordinating conjunction “and.”

Introductory Clause Followed by Independent Clause:

2. Upon finishing the challenging course, which required immense dedication, she celebrated her achievement.

Here, the comma follows the introductory clause, setting it apart from the independent clause that follows.

Complex Sentence with Subordinate Clause:

3 While the team was finalizing the project, which had taken months of hard work, they encountered unforeseen challenges.

The comma is placed after the subordinate clause “which had taken months of hard work” to signal the beginning of the independent clause.

Complex Sentence with Appositive Phrase:

4. The novel, a masterpiece of modern literature, which explores complex themes, has garnered international acclaim.

A comma is used before and after the appositive phrase “a masterpiece of modern literature” to provide additional information about the novel.

Complex Sentence with Non-Restrictive Clause:

5. The conference, which attracted experts from around the world, provided valuable insights into emerging technologies.

The comma is placed before and after the non-restrictive clause “which attracted experts from around the world” to add extra information without changing the sentence’s core meaning.

In each example, the strategic use of commas enhances the readability of complex sentences, helping to distinguish different components and maintain clarity.

Comma Rules in Formal Writing

In formal writing, adherence to specific comma rules is crucial. Use commas judiciously, following grammar conventions to maintain a polished and professional tone.

Incorporating Commas in Lists with “Which”

When incorporating lists containing “which,” each item should be separated by a comma. This ensures clarity and prevents confusion among readers.

1. The project involved research studies, which gathered data, interviews, which collected personal insights, and surveys, which gauged public opinions.

Here, commas separate the distinct elements within the list.

Addressing Ambiguity with Commas

Commas play a pivotal role in eliminating ambiguity. Consider this sentence:

I love my parents, which brings me joy.

Without a comma before “which,” the sentence could imply that the speaker loves their parents because it brings joy, introducing unintended confusion.

Comma Usage in Dialogue with “Which”

Mastering the use of commas in dialogue, especially when “which” is involved, is crucial for clear and effective communication. Here’s a concise guide to help you navigate the proper comma usage in dialogue:

Commas in dialogue help maintain a natural flow and indicate pauses.

  1. When “which” is used in dialogue to introduce additional information, a comma is placed before and after it. 
  2. If “which” introduces a parenthetical phrase within dialogue, use commas to set it apart.
  3. In instances where “which” leads to an independent clause within dialogue, use commas to separate clauses.
  4. Use commas after “which” in dialogue to emphasize or highlight additional information.
  5. When using “which” in more complex sentences within dialogue, employ commas to enhance readability.
  6. In cases where the information introduced by “which” is essential to the dialogue, omit commas.
  1. Example 1: “She exclaimed, ‘I found the missing key, which was under the couch!'”
  2. Example 2: *”He explained, ‘The experiment, which took months to plan, was a tremendous success.'”
  3. Example 3: “She decided to join the project, which surprised her colleagues, and also volunteered for additional responsibilities.”
  4. Example 4: “As she spoke, she shared her insights into the industry, which, unbeknownst to her, captivated the entire audience.”
  5. Example 5: “The team discussed various strategies, which, interestingly, led to a groundbreaking solution.”
  6. Example 6: “She asked, ‘Which document outlines the project requirements?'”

By adhering to these guidelines, you’ll seamlessly incorporate commas into dialogue, ensuring a natural and coherent flow in your writing.

Commonly Asked Questions

Should I always use a comma before “which” in a sentence?

No, only use a comma before “which” in non-restrictive clauses. Restrictive clauses do not require a preceding comma.

Is it acceptable to use a comma after “which” in every sentence?

No, a comma after “which” is only necessary in non-restrictive clauses. Restrictive clauses should not have a comma before “which.”

How can I determine if a clause is restrictive or non-restrictive?

A restrictive clause is essential to the sentence’s meaning and should not be set off with commas. A non-restrictive clause provides additional information and is separated by commas.

Can I use multiple commas in a sentence with “which”?

Yes, in complex sentences, you may need multiple commas to separate clauses and maintain clarity.

What role do commas play in formal writing?

Commas in formal writing help maintain a polished and professional tone, ensuring adherence to grammatical conventions.


In mastering the art of using commas before or after “which,” clarity and precision are paramount. By understanding the nuances of restrictive and non-restrictive clauses, writers can wield commas effectively, enhancing the overall coherence of their sentences.