Non-Restrictive Clauses and Commas: Rules & Examples (2026)

Ever get tangled up in commas and clauses? You’re not alone. Simply put, non-restrictive clauses are descriptive phrases that add extra, non-essential information to a sentence, and they are always set off by commas. Grammar rules can feel complicated, but understanding how to use non-restrictive clauses and commas is a simple way to make your writing clearer, more sophisticated, and more precise.

Think of a non-restrictive clause as a “by the way” comment you slide into a sentence. It adds interesting, extra information, but it isn’t essential to the sentence’s core meaning. Let’s break down how they work and how to punctuate them perfectly.

What Is a Nonrestrictive Clause?

A nonrestrictive clause is a part of a sentence that provides additional detail about a noun that is already specific. Because this information is extra, you can remove the clause without changing the fundamental meaning of the sentence. The word ‘comma’ itself comes from the Greek word kómma, which means ‘something cut off’ or a ‘short clause.’ This is a fitting description for a phrase that can be neatly snipped from a sentence.

These are also known as non-essential or non-defining clauses, which helps explain their purpose: they don’t define the noun, they just describe it a bit more. A key part of using non-restrictive clauses and commas correctly is understanding what they are.

For example, in the sentence, “My car, which is ten years old, still runs well,” the clause “which is ten years old” is non-restrictive. The main point is that my car runs well. The fact that it’s a decade old is just a bonus detail.

Restrictive vs. Nonrestrictive Clauses: The Key Difference

To really understand non-restrictive clauses, it helps to compare them to their counterpart: restrictive clauses.

• A restrictive clause is essential information. It restricts or limits the noun it describes to a specific one out of a group of possibilities. You cannot remove it without confusing the reader or changing the meaning. It is not set off by commas.
• A non-restrictive clause is non-essential information. It describes a noun that is already specific and unique. You can remove it, and the sentence’s main point remains intact. It is always set off by punctuation, usually commas.

Let’s look at an example that makes the difference crystal clear:

1. Restrictive: The students who studied hard passed the exam.
   • This implies that only the students who studied hard passed. The clause “who studied hard” is essential because it tells us which specific group of students passed.
2. Non-restrictive: The students, who had studied hard, passed the exam.
   • This implies that all the students passed the exam. The clause “who had studied hard” is just extra information, perhaps explaining why they were successful.

The only difference is the punctuation, but it completely changes the meaning of the sentence. This is why getting non-restrictive clauses and commas right is so important.

The Golden Rule: Comma Placement for Non-Restrictive Clauses

The punctuation rule for non-restrictive clauses and commas is simple and consistent: always set off a non-restrictive clause with commas.

• If the clause is in the middle of the sentence, place a comma before and after it.
  • Example: Our principal, who has a doctorate, gave a great speech.
• If the clause is at the end of the sentence, place a comma before it.
  • Example: I’m visiting my parents in Ohio, where I grew up.

This rule isn’t new; the modern comma was standardized for print by Italian publisher Aldus Manutius in the 1490s to bring clarity to the written word. Today, major style guides like The Chicago Manual of Style and the AP Stylebook uphold this fundamental rule for setting off non-essential information.

A handy trick is the “parentheses test.” If you can put the clause in parentheses and the sentence still makes perfect sense, it’s non-restrictive and needs commas. For example, “Our principal (who has a doctorate) gave a great speech” works perfectly.

On the other hand, you should never place commas around a restrictive clause, as this would incorrectly signal that the information is optional when it’s actually crucial.

Which vs. That: A Quick Guide to Choosing the Right Word

One of the most common grammar questions involves the words “which” and “that.” While the rules can be flexible, a simple guideline followed in American English will make your writing instantly clearer.

• Use that for restrictive clauses (the essential kind) with no comma.
• Use which for non-restrictive clauses (the extra info kind) with a comma.

Let’s see this in action:

• Restrictive: I read the book that you recommended. (The clause “that you recommended” is essential to identify which book.)
• Non-restrictive: I’m reading “Dune,” which you recommended. (The clause “which you recommended” is extra information. We already know the specific book is “Dune.”)

This distinction was formally popularized in H.W. Fowler’s influential 1926 style guide, A Dictionary of Modern English Usage. A famous historical example that uses the non-restrictive “which” is from Franklin D. Roosevelt’s 1941 Pearl Harbor speech: “a date which will live in infamy.” Following this rule removes ambiguity for your reader. It’s a key distinction that educators focus on. For teachers looking to create practice materials on this topic, it can be time-consuming to come up with clear examples. TeachTools’ Academic Content tool can generate leveled examples in seconds. With an AI assistant like TeachTools, you can instantly generate quizzes and worksheets that reinforce the correct use of non-restrictive clauses and commas. If you’re exploring AI for the classroom, review this FERPA‑compliant AI tools checklist to keep student data protected.

More Than Just ‘Which’: A Look at Relative Pronouns

Non-restrictive clauses are introduced by relative pronouns. Choosing the right one depends on what you’re referring to. If you’re supporting English learners, this guide on teaching English language learners offers strategies for modeling pronouns and clauses. To scaffold for multilingual students, you can translate example sentences into home languages before practicing in English.

• Who: Refers to people (as the subject).
  • Example: The manager, who is very experienced, approved the project.
• Whom: Refers to people (as the object of a verb or preposition). It is more formal and less common in casual speech.
  • Example: The candidate, whom the committee interviewed, was highly qualified.
• Whose: Shows possession for people or things.
  • Example: The author, whose book became a bestseller, visited our school.
• Which: Refers to things and animals.
  • Example: The Eiffel Tower, which is in Paris, is a famous landmark.
• That: Refers to things (and sometimes people) but is only used in restrictive clauses.
  • You would not say: The Eiffel Tower, that is in Paris, is a famous landmark.

Let’s See It in Action: Examples of Non-Restrictive Clauses

The best way to understand the impact of non-restrictive clauses and commas is with a classic example that highlights the change in meaning.

• Sentence 1: My brother, who lives in New York, is a doctor.
  • The commas signal that “who lives in New York” is a non-restrictive clause. This sentence implies the writer has only one brother, and as an extra piece of information, he happens to live in New York.
• Sentence 2: My brother who lives in New York is a doctor.
  • The absence of commas signals a restrictive clause. This sentence implies the writer has more than one brother, and they are specifying that it’s the one living in New York who is a doctor, not a different brother who might live elsewhere.

A tiny punctuation change creates a completely different family tree!

What About Appositives? Handling Commas with Noun Phrases

An appositive is a noun or noun phrase that renames another noun right beside it. Just like clauses, appositives can be restrictive or non-restrictive, and they follow the same comma rule.

If the appositive provides non-essential information about an already specific noun, it’s non-restrictive and needs commas.

• Non-restrictive appositive: Dr. Evans, our family doctor, is retiring.
  • “Our family doctor” renames “Dr. Evans.” Since his name already identifies him, the appositive is extra information and is set off by commas.
• Restrictive appositive: The author Jane Austen wrote “Pride and Prejudice.”
  • “Jane Austen” is essential to identify which author we mean. Without her name, the sentence “The author wrote ‘Pride and Prejudice’” is unclear. Therefore, no commas are used.

Putting It All Together: Using Non-Restrictive Clauses in Your Writing

Mastering non-restrictive clauses and commas elevates your writing from basic to sophisticated. It allows you to combine ideas and add layers of detail smoothly, avoiding a series of short, choppy sentences.

Instead of writing: “My hometown is small. It has a famous museum.”
You can write: “My hometown, which is small, has a famous museum.”

This skill is crucial in professional and academic writing, where precise use of non-restrictive clauses and commas is key. A misplaced comma can alter the meaning of a contract or a research paper. For grading periods, clear grammar also strengthens report card narratives, and you can use the Report Card Comment generator to draft polished, specific feedback fast.

For educators, teaching this nuance is vital. Creating clear, correct, and engaging materials is the best way to help students succeed. If you’re tired of spending hours building lesson plans and worksheets from scratch, let AI do the heavy lifting. The tools at TeachTools are designed by educators to produce high quality, classroom ready content in minutes, so you can focus on teaching.

Frequently Asked Questions about Non-Restrictive Clauses and Commas

1. What’s the easiest way to tell if a clause is non-restrictive?
The simplest test is to remove the clause from the sentence. If the main point of the sentence is still clear and grammatically correct, the clause was non-restrictive and needs commas.

2. Do I always need a comma before the word “which”?
When “which” introduces a non-restrictive clause (providing extra information), you should use a comma before it. In American English, this is the most common and recommended usage.

3. Can I ever use “that” with commas?
No, the relative pronoun “that” is used to introduce restrictive (essential) clauses and should not be set off by commas. If a clause needs commas, you should use “which” (for things) or “who” (for people).

4. Why is the comma so important in “My friend, who is a pilot,…”?
The commas signal that you have only one friend (or one relevant friend in this context), and you’re adding the bonus fact that she is a pilot. Without the commas (“My friend who is a pilot…”), you would be implying that you have multiple friends, and you are specifying the one who is a pilot.

5. Are non-restrictive clauses and appositives the same thing?
They are very similar in function but structurally different. A non-restrictive clause has a subject and a verb (e.g., “who is a pilot”), while a non-restrictive appositive is a noun or noun phrase (e.g., “a skilled pilot”). Both provide extra information and are set off by commas.