Restrictive and Nonrestrictive Clauses – What’s the Difference?

Restrictive and Nonrestrictive Clauses play a vital role in shaping clear and meaningful writing. In my writing journey, I often stood at a crossroads, unsure how to make a sentence sound just right. When I tried adding extra information, it sometimes changed the meaning in unexpected ways. That’s when I uncovered the real difference between restrictive and nonrestrictive clauses– a turning point that showed me how grammar brings clarity and prevents confusion for readers.

Through continuous practice, I learned that using these clauses properly gives writers complete control over sentence flow and detail. It ensures readers receive exactly what you intend- no more, no less. Mastering this concept helps your words move from vague to vivid, creating writing that is both clear and confidently structured.

Introduction: Why Clauses Matter in English Grammar

Every time you write a sentence, you’re choosing words that shape meaning. You might not notice it- but even a single comma or the choice between that and which can change the meaning of a sentence dramatically. The difference between restrictive and nonrestrictive clauses matters because it affects precision, clarity, and readability. If you want your writing to be crisp and correct, mastering these clauses is a must. In this article, you’ll learn what each type of clause does, how to spot them, how punctuation plays a role, and, importantly, how to use them effectively in real-world writing.

Understanding Clauses: The Building Blocks of Sentences

A clause is a group of words with a subject and a verb. It might stand on its own (an independent clause) or depend on another clause to complete its meaning (a dependent clause). In the context of this article, we focus on adjective (relative) clauses– those that modify nouns or noun phrases. For example: “The man who called is my friend.” The part that is called is a relative clause. What makes it restrictive or nonrestrictive depends on how essential that clause is to identifying the noun it modifies.

Relative clauses often begin with a relative pronoun such as who, whom, whose, which, or that. The choice of pronoun plus punctuation often signals whether the clause is restrictive or nonrestrictive. Getting this right improves your writing and helps you avoid ambiguity.

What Are Restrictive Clauses? (Definition + Function)

A restrictive clause (also called defining or essential) gives information necessary to identify the noun it modifies. If you remove the clause, the meaning changes significantly or becomes unclear. For instance:

• “The students who study hard earn good grades.” –  The clause who study hard tells us which students. Without it, “The students earn good grades” lacks clarity.
• “The book that I borrowed is on the shelf.” –  Here that I borrowed restricts which book.

A key hallmark: no commas should separate a restrictive clause from the rest of the sentence, because the clause is integral to the meaning.

Characteristics of Restrictive Clauses

Here are features you’ll often see in restrictive clauses:

• They often begin with relative pronouns like that, who, whom, whose, or sometimes which (though usage varies).
• They do not use commas to set off the clause- the meaning is part of the noun phrase.
• If you remove the clause, the sentence’s meaning either changes or becomes ambiguous.
• They typically define which one (of many) is meant.
• They tend to appear when dealing with general or multiple nouns (not unique ones). For example: “The cars that are red will be painted.”
• Relative pronouns sometimes can be omitted when they act as the object of the clause: e.g., “The results I obtained were surprising.” Where that/which could go but is omitted.

Here’s a mini-table summarizing:

Feature	Restrictive Clause
Commas used?	No
Can the clause be omitted without changing the meaning?	No
Purpose	Identify or restrict the noun
Common pronouns	that, who, which (varies)
Examples	The students who arrived late missed the start.

Identifying Restrictive Clauses in Real Sentences

Let’s practice spotting them. Here’s a step-by-step guide:

1. Find the clause: look for “who/which/that/whom/whose” plus a verb.
2. Remove the clause and read the sentence.
3. Check meaning: If the sentence loses meaning or becomes ambiguous, it’s likely restrictive.
4. Check commas: Lack of commas suggests restrictive.

Examples

Sentence	Clause	Remove clause → Result	Verdict
The students who arrived late missed lunch.	who arrived late	The students missed lunch. (But which students?)	Restrictive
My red car broke down yesterday.	which is red	My car broke down yesterday. (Still clear)	Nonrestrictive
The house that Jack built is haunted.	that Jack built	The house is haunted. (Which house?)	Restrictive

“In the example: The employees who work remotely requested further training, the clause specifies which employees. Drop it and the meaning changes.”

Quick check-list

• Does it tell which one (of several) the noun is? → Likely restrictive.
• Does omitting it change which noun you mean? → Restrictive.
• Are there no commas setting it off? → Probably restrictive.

What Are Nonrestrictive Clauses? (Definition + Function)

A nonrestrictive clause (also called non-defining or nonessential) adds extra, non-essential information about a noun whose identity is already clear. If you remove the clause, the sentence remains meaningful and recognizable. For example:

• “My brother, who lives in New York, is visiting this week.” –  The clause who lives in New York adds extra info; we already know which brother.
• “This painting, which was created in 1910, is still remarkable.” The clause provides background, not necessary identity.

Nonrestrictive clauses are set off by commas (or sometimes dashes) because the extra information acts like a parenthesis in the sentence.

Commas and Nonrestrictive Clauses: The Clarity Factor

Punctuation plays a big role in signaling nonrestrictive clauses. Using commas correctly helps your readers understand whether the clause is essential or just extra.

Why commas matter

• They tell the reader: “Pause here –  this info is additional.”
• A missing comma or a misplaced comma can alter the meaning entirely. For example:
  • “The CEO who had lunch with us approved the plan.” → Only that CEO approved.
  • “The CEO, who had lunch with us, approved the plan.” → The CEO (who happened to have lunch) approved the plan –  the lunch detail is incidental.
• According to the Canadian government’s drafting guidelines:
  “Because a restrictive element is essential … it should not be set off by commas … a non-restrictive element should be set off by punctuation.”

Comma rules at a glance

• If the clause is in the middle: use a comma before and after the clause.
• If the clause ends the sentence: use a comma before the clause and then the period.
• If the clause starts the sentence: it’s less common, but still separate it with commas.

Visual breakdown

Sentence A (restrictive): The students who arrived late missed lunch. No commas –  the clause identifies which students. Sentence B (nonrestrictive): My students, who arrived late, missed lunch. Commas –  the clause adds extra info; you already know which students.

Remember: commas matter for meaning, flow, and readability.

The Great “That” vs. “Which” Divide

Many writers get stuck over whether to use that or which. The correct choice often depends on whether the clause is restrictive or nonrestrictive.

“That” vs “Which” –  Quick rule

• Use that for restrictive clauses (essential).
• Use which for nonrestrictive clauses (extra info) –  and place commas around the clause

Examples

• Restrictive: “The book that you lent me is fascinating.” → “that you lent me” defines which book.
• Nonrestrictive: “This novel, which won several awards, is fascinating.” → “which won several awards” adds extra info.

Exceptions and style notes

• In British English and informal writing some flexibility exists; “which” is used more broadly.
• The style guides (especially US academic writing) tend to favour that for restrictive.
• If you’re ever unsure, test the clause by removing it. If the meaning remains unambiguous, then you likely need which + commas. If meaning changes, use that, no commas.

American vs. British English: Clause and Punctuation Differences

Regional style differences may influence how you write clauses. Knowing them improves your writing for different audiences (academic, business, international).

American English

• Strong preference: restrictive clause = that, no commas; nonrestrictive clause = which, commas.
• More rigid rules in academic and technical writing.

British English

• More allowances: “which” might be used in both restrictive and nonrestrictive clauses.
• Punctuation rules (like comma usage) may be more flexible.
• For global audiences: make sure your rule is consistent. If you begin one way, stick with it throughout the piece.

Tips for global writing

• Choose one style (US or UK) and maintain consistency.
• If your audience is international or mixed, favour clarity over dogmatic rule-application.
• Consider making a brief statement or note that your usage follows a particular style (e.g., “In this article, I use that for essential clauses and which for non-essential ones”).

How Clauses Affect Tone and Writing Style

Beyond correctness, the way you use clauses affects the tone, flow, and readability of your writing. Here’s how:

Using clauses for rhythm and emphasis

• Short sentences boost impact: “She arrived. We waited.”
• Clauses can allow for more complex ideas without confusion: “The candidate who won the election pledged change.”
• Using nonrestrictive clauses gives your writing a conversational flavour: “My colleague, who loves jazz, will present tomorrow.” –  the extra info feels like a side note.

Tone and voice considerations

• Formal writing (academic, technical) often uses restrictive clauses for precision and avoids stray commas.
• Storytelling or blog writing often uses nonrestrictive clauses for parenthetical details that engage readers.
• Overusing restrictive clauses can make writing feel dense; too many nonrestrictive clauses can make writing ramble.

Example from literature/journalism

“The author, who had written dozens of novels, spoke to a crowded room.” Here, the clause adds rhythm and background: nice for engagement. Compare: “The author who had written dozens of novels spoke to a crowded room.” Here, the clause restricts “which author” (implying multiple authors). Tone: more formal and precise.

Style checklist

• Ask: Does the clause help define which noun? If yes → restrictive.
• Ask: Is the info simply extra, not needed to identify the noun? → nonrestrictive.
• Use clause variety: mix simple independent clauses with relative clauses for dynamic flow.
• Keep sentences readable: alternate shorter and longer sentences.
• Make sure each clause choice supports your writing goal (clarity, style, engagement).

Common Mistakes Writers Make (and How to Fix Them)

Even experienced writers slip up when it comes to clauses. Here’s how to avoid common errors.

Mistake #1: Using commas incorrectly

• “The students, who study hard, passed the test.” –  implies all students study hard.
• Solution: Clarify your meaning. If you mean only some students: “The students who study hard passed the test.”

Mistake #2: Using “which” in restrictive clauses (US style)

• “The car which I bought last week is already scratched.” –  many style guides prefer that when clause is essential.
• Fix: “The car that I bought last week is already scratched.”

Mistake #3: Omitting the pronoun incorrectly or confusing “who” vs. “whom”

• Example: “The people whom attended the meeting…” –  should be who attended since “who” is the subject of the clause.
• Fix: Use who for subjects, whom for objects (though “whom” is less common in everyday writing).

Mistake #4: Overloading a sentence with multiple dependent clauses

• “The manager, who hated meetings, that she attended, interrupted the discussion.” –  messy.
• Better: Simplify and break into two sentences or restructure.

Mistake #5: Ignoring the reader’s perspective

• If your reader must guess which noun you mean, revisit your clause.
• Clarity beats “creative complexity” in most professional writing.

Self-editing checklist

• Remove the clause- does meaning change? If yes → likely restrictive.
• Check for commas- are they present? If yes → likely nonrestrictive.
• Choose that for essential (restrictive) in US style, which is for nonessential.
• Ensure the pronoun (“who/whom”) matches its role in the clause.
• Read aloud- if you feel a pause/commas belong, you may have a nonrestrictive clause.

Exercises: Practice Identifying Clauses

Try these exercises to sharpen your recognition of restrictive vs nonrestrictive clauses. Write your answers (restrictive or nonrestrictive) and revisit the reasoning.

Exercise sentences

1. The author who won the prize lives nearby.
2. My car, which I bought last year, needs repair.
3. Students who arrive late miss the introduction.
4. The office, which is on the fifth floor, has a great view.
5. The dog that barked all night belongs to them.

Answers & explanation

Sentence	Restrictive or Nonrestrictive?	Why
1	Restrictive	“Who won the prize?” defines which author.
2	Nonrestrictive	Commas – clause adds info about the car, not needed to identify.
3	Restrictive	“Who arrives late?” identifies which students.
4	Nonrestrictive	Clause after commas – description of office.
5	Restrictive	“That barked all night” identifies which dog.

Writing task

Rewrite the following by changing the clause type and meaning:

• Original: “The city that never sleeps attracts tourists.” (restrictive)
• Changed: “New York, which never sleeps, attracts tourists.” (nonrestrictive) Note how meaning shifts.

Related Grammar Concepts (Deep-Dive Links)

While restrictive and nonrestrictive clauses are the core focus, here are quick link-in ideas to deepen your grammar mastery –  especially useful for advanced or academic writing.

Verb Tense Agreement in Complex Clauses

When your clause has its own verb, make sure the tense agrees logically with the main clause. Clauses shouldn’t create confusion by shifting time without reason.

Subjective Case: “Who” or “Whom”?

In relative clauses:

• Use who if the relative pronoun is the subject of the clause.
• Use whom if it’s the object. For example: “The person whom I saw…” vs “The person who saw me…”

“Those Who” vs. “Those Whom”

• Use who after “those” when the clause subject is doing the action: “Those who apply will be considered.”
• “Whom” feels formal/uncommon in modern writing; many writers avoid it unless necessary.

Starting a Sentence with “During” – Comma Rules

When you begin a sentence with a clause introduced by during, evaluate if you need a comma. Example: “During the meeting, we discussed results.” vs “During the meeting, we discussed results.” Both can work; choose depending on pace and emphasis.

Optional: Optative Sentences

An optative sentence expresses a wish or hope (e.g., “May you succeed!”). While not directly tied to restrictive/nonrestrictive clauses, understanding variations in sentence type enriches your writing toolkit.

“All Was” or “All Were” – Which Is Correct?

Plurality matters. Generally, use all were with plural nouns and all was with singular or mass nouns. E.g., “All of the cookies were eaten.” vs “All was quiet.” This doesn’t directly relate to clauses, but good to master in the same grammar session.

How to Master Clauses in Everyday Writing

Knowing the rules is one thing. Using them confidently in essays, business emails, blog posts or fiction is another. Here are practical tips:

Practical Applications

• Business writing: Use restrictive clauses to specify projects, clients, and deadlines. Keep sentences concise.
• Academic writing: Precision matters. Use restrictive clauses and correct punctuation for clarity.
• Blog or storytelling: Throw in nonrestrictive clauses for colorful detail without confusing your reader: “My friend, who runs marathons, joined us for coffee.”
• Emails: Keep it simple. If the extra information isn’t essential, consider rewriting rather than adding a long nonrestrictive clause.

Editing Tips

• Read your draft aloud. Does a clause feel like needed info or extra?
• Remove the clause temporarily. If the meaning changes, note as restrictive.
• Check comma usage around clauses.
• Choose that vs which consistently if writing in US style.
• Prioritize reader clarity: make sure the noun you modify is easy to identify.

Writing Habit

• Keep a grammar journal: collect sentences you read that use clauses well.
• Practice rewriting a sentence by changing a clause’s type and see how the tone changes.
• When uncertain, lean toward a simpler structure: avoid burying the key noun under several nested clauses.

One Comma Can Change Everything

Mastering restrictive and nonrestrictive clauses gives you real power as a writer. It’s not just about which comma or pronoun you use- it’s about meaning, reader understanding, and style. Here’s a quick recap:

• Restrictive clauses: essential info; no commas; often “that” in US style.
• Nonrestrictive clauses: extra info; require commas; often “which.”
• The difference affects clarity and tone.
• Choose your style (US or UK) and be consistent.
• Use clauses deliberately: for precision, rhythm, or flavour.

Next time you write, pause at your clause. Ask: Is this information defining the noun, or simply adding flavour? Your answer helps you decide punctuation, pronouns, and structure. In doing so, your writing becomes sharper, more readable, and more professional.

Conclusion

Understanding restrictive and nonrestrictive clauses isn’t just about grammar rules –  it’s about precision and style. These clauses determine how clearly your ideas flow and how well your message resonates with readers. A restrictive clause defines or limits meaning; without it, the sentence loses essential information. A nonrestrictive clause, however, simply adds extra detail –  like a gentle whisper, not the core message.

When you master this difference, your writing becomes sharper, more persuasive, and more readable. Readers appreciate clarity, and strong sentence structure creates that clarity. The right placement of commas around nonrestrictive clauses prevents confusion and keeps your writing polished. On the other hand, restrictive clauses, which never take commas, make your intent direct and confident.

Whether you’re writing essays, reports, or blog posts, the correct use of these clauses shapes how your readers interpret meaning. Misplacing a comma or choosing the wrong relative pronoun (“that” vs. “which”) can alter your entire message –  a small mistake with a big impact.

If you want your writing to sound professional and human, take time to identify which details are essential and which are extra. Use restrictive clauses to define your subject and nonrestrictive clauses to enhance it. Combine this understanding with consistent editing, and you’ll produce content that communicates with precision and authority.

Language mastery comes from awareness and intention –  the ability to make every clause count. Remember: the goal isn’t to follow rules blindly but to write with clarity and impact. When you know how restrictive and nonrestrictive clauses work, your sentences will not only be grammatically correct but also elegantly crafted.

FAQs

What is the main difference between restrictive and nonrestrictive clauses?

A restrictive clause provides essential information that defines the noun it modifies and is not set off by commas. A nonrestrictive clause adds extra, nonessential information and is always separated by commas. For example: “The students who studied hard passed the test” (restrictive), versus “The students who studied hard passed the test” (nonrestrictive).

When should I use commas with clauses?

Use commas only with nonrestrictive clauses. These clauses add additional information that doesn’t change the core meaning of the sentence. Restrictive clauses, on the other hand, do not need commas because the information they provide is vital to identifying the subject.

How do I know whether to use “that” or “which”?

In American English, “that” introduces restrictive clauses, while “which” introduces nonrestrictive clauses. Example: “The car that I bought is new” (essential). “The car, which I bought last week, is new” (extra information). This distinction keeps your writing grammatically precise and easy to follow.

Can a clause be both restrictive and nonrestrictive?

No, a clause cannot serve both roles in the same sentence. It’s either essential to the noun (restrictive) or extra (nonrestrictive). However, a sentence can contain both types in different places, helping balance clarity and richness of detail in your writing.

Why are restrictive and nonrestrictive clauses important for writers?

They are crucial because they control meaning, rhythm, and clarity. Knowing when to define versus elaborate helps you craft stronger, more precise sentences. Readers understand your intent clearly, and your writing gains a professional, natural flow –  an essential skill for all effective communicators.