The comma is one of the most commonly used punctuation marks in the English language, yet it can also be one of the most misused. Despite its frequent appearance in written communication, many people struggle to understand when and how to use a comma correctly. In this guide, we’ll explore everything there is to know about commas, from their definition and basic functions to the specific rules and exceptions that govern their usage.
What Is a Comma?
A comma is a punctuation mark (,) used to indicate a pause between different parts of a sentence. It helps clarify meaning by separating elements within a sentence, thereby ensuring that the sentence flows in a way that is easy for readers to follow. Commas are crucial for providing structure to a sentence, marking boundaries between ideas, and preventing ambiguity.
While the comma might seem like a simple mark, it serves several purposes and plays a crucial role in sentence structure, meaning, and readability. Overusing or misplacing commas can lead to confusion, while omitting them where they are needed can result in unclear or incorrect sentences.
When to use commas
The comma has multiple functions, each of which helps organize and clarify the meaning of a sentence. Below are the primary uses of commas:
- Separating items in a series
- Before conjunctions in compound sentences
- After introductory elements
- Setting off nonessential clauses or phrases
- Before direct addresses
- Between coordinate adjectives
- Before and after transitional expressions
- Setting off interjections or mild exclamations
- With dates, addresses, and titles
- Before the quotation marks in direct speech
- To separate coordinate nouns
- In large numbers
- After certain introductory adverbs
- To separate adjectives in a list describing the same noun
- To set off a tag question
- In numbers with decimals
1. Using Commas in Lists
One of most common use of commas is in lists. But where exactly do you place commas in a list? And what about the controversial Oxford comma? Let’s break it down.
When to Use Commas in Lists
Commas are used to separate items in a series of three or more. This helps avoid confusion and makes your writing clearer. Here’s a basic example:
- I bought apples, oranges, and bananas.
Each item in the list is separated by a comma, making it easy to read.
The Oxford Comma: Is It Necessary?
The Oxford comma (also called the serial comma) is the final comma before the conjunction in a list. Some style guides require it, while others consider it optional. Here’s how it looks in a sentence:
- I love reading, traveling, and cooking. (With Oxford comma)
- I love reading, traveling and cooking. (Without Oxford comma)
While both are correct, using the Oxford comma can prevent ambiguity. For example:
- I dedicate this book to my parents, Oprah Winfrey and Elon Musk.
Without the Oxford comma, it sounds like Oprah and Elon are the writer’s parents. Adding a comma clears up the confusion:
- I dedicate this book to my parents, Oprah Winfrey, and Elon Musk.
When Not to Use a Comma in a List
You don’t need a comma if the list has only two items:
- I love coffee and tea. (No comma needed)
Also, avoid adding a comma before the first item or after the last item in the list:
- Incorrect: I love, coffee, tea, and juice.
- Correct: I love coffee, tea, and juice.
Commas in Complex Lists
If items in your list already contain commas, use semicolons to separate them for clarity:
- On our trip, we visited Paris, France; Rome, Italy; and Madrid, Spain.
This prevents confusion between individual list items.
2. Commas before conjunctions in compound sentences
When writing, you often need to join two complete thoughts (independent clauses) into one sentence. One of the most common ways to do this is by using a comma along with a coordinating conjunction like for, and, nor, but, or, yet, so (FANBOYS).
Rule: Use a Comma Before the Coordinating Conjunction
When two independent clauses are joined by a coordinating conjunction, always place a comma before the conjunction.
✅ Correct Example:
Emma loves to read, but she also enjoys painting.
(“Emma loves to read” and “she also enjoys painting” are both complete sentences, so they need a comma before “but.”)
✅ Correct Example:
The sun was shining, so we decided to go for a walk.
(Each part of the sentence can stand alone, so a comma is needed before “so.”)
What Happens If You Skip the Comma?
Leaving out the comma can make the sentence unclear or confusing.
❌ Incorrect:
I wanted to go for a run but it started raining.
(Without a comma before “but,” the sentence feels rushed and harder to read.)
✅ Fixed:
I wanted to go for a run, but it started raining.
What If the Second Clause Isn’t Independent?
If the second part of the sentence is not an independent clause (it doesn’t form a complete sentence on its own), don’t use a comma.
✅ Correct Example:
We went to the beach and played volleyball.
(“Played volleyball” isn’t a full sentence, so no comma is needed.)
✅ Correct Example:
She enjoys hiking and prefers mountain trails.
(The second part isn’t independent, so no comma is necessary.)
Common Mistakes to Avoid
1️⃣ Comma Splice (Joining Two Independent Clauses with Just a Comma)
❌ She loves coffee, he prefers tea.
✅ She loves coffee, but he prefers tea.
✅ She loves coffee. He prefers tea. (Use a period instead.)
✅ She loves coffee; he prefers tea. (A semicolon also works.)
2️⃣ Using a Comma Before Every “And” or “But”
❌ I like pizza, and I like pasta, and I like burgers.
✅ I like pizza, pasta, and burgers. (A list doesn’t need multiple coordinating conjunctions.)
3. Commas with Relative Clauses
A non-restrictive relative clause adds extra information to a sentence, but the sentence would still make sense without it. To properly set it apart, use commas before and after the clause.
Rule: Use Commas to Set Off Non-Restrictive Relative Clauses
A non-restrictive relative clause (also called a non-essential clause) provides additional information that is not necessary to identify the noun it describes. Since it’s just extra information, it should be separated by commas.
✅ Correct Example:
My brother, who lives in New York, is visiting next week.
(“Who lives in New York” is extra information. If we remove it, the sentence still makes sense: “My brother is visiting next week.”)
✅ Correct Example:
The Eiffel Tower, which was built in 1889, is a famous landmark.
(Removing “which was built in 1889” still leaves a complete sentence: “The Eiffel Tower is a famous landmark.”)
What Happens If You Skip the Commas?
Leaving out commas can make your sentence unclear or misleading.
❌ Incorrect:
My sister who works at a hospital is coming over.
(This suggests you have more than one sister, and you’re specifying which one.)
✅ Fixed:
My sister, who works at a hospital, is coming over.
(This tells us you have only one sister, and the fact that she works at a hospital is extra information.)
Restrictive vs. Non-Restrictive Relative Clauses
A restrictive clause (essential clause) does not need commas because it is necessary for meaning.
Restrictive Clause (No Commas)
Students who study hard get good grades.
(The clause is essential because it tells us which students get good grades.)
Non-Restrictive Clause (Use Commas)
Students, who often feel stressed, need to take breaks.
(The clause adds extra information about students in general.)
4. Commas with appositives
An appositive is a noun or noun phrase that renames or explains another noun right next to it. When an appositive is nonessential (meaning it provides extra information but isn’t necessary to identify the noun), it should be set apart with commas.
Rule: Use Commas to Set Off Nonessential Appositives
A nonessential appositive adds extra information but isn’t needed to understand the sentence. Since it’s just additional detail, it should be surrounded by commas.
✅ Correct Example:
My friend, Sarah, loves to paint.
(“Sarah” is an extra detail—if we remove it, the sentence still makes sense: “My friend loves to paint.”)
✅ Correct Example:
The Eiffel Tower, a famous landmark in Paris, attracts millions of tourists every year.
(“A famous landmark in Paris” is additional information about the Eiffel Tower.)
What Happens If You Skip the Commas?
Leaving out commas can change the meaning of the sentence.
❌ Incorrect:
My brother James is an engineer.
(This suggests that you have more than one brother and you are specifically referring to James.)
✅ Fixed:
My brother, James, is an engineer.
(This suggests that you have only one brother, and his name is James.)
Essential vs. Nonessential Appositives
🔹 Essential Appositives (No Commas)
When the appositive is necessary to identify the noun, don’t use commas.
✅ Example:
The poet Maya Angelou is known for her inspirational works.
(Here, “Maya Angelou” is essential because it tells us which poet we’re talking about.)
🔹 Nonessential Appositives (Use Commas)
When the appositive is extra information, use commas.
✅ Example:
Maya Angelou, a famous poet, is known for her inspirational works.
(“A famous poet” is additional detail, not required to identify Maya Angelou.)
5. Commas with introductory phrases
An introductory phrase is a group of words that appears at the beginning of a sentence and provides extra information before the main clause. To make sentences clear and easy to read, a comma is usually needed after an introductory phrase.
Rule: Use a Comma After an Introductory Phrase
If a phrase appears at the beginning of a sentence and sets up the main idea, it should be followed by a comma.
✅ Correct Example:
After the meeting, we went out for lunch.
(The phrase “After the meeting” provides background information but isn’t necessary for the main sentence.)
✅ Correct Example:
In the morning, I like to go for a run.
(The introductory phrase “In the morning” sets up the time but isn’t the main idea.)
✅ Correct Example:
Considering the circumstances, she handled the situation well.
(The phrase “Considering the circumstances” provides context before the main clause.)
When Is a Comma Optional?
If the introductory phrase is short (fewer than four words), a comma is usually optional unless needed for clarity.
✅ Both Correct:
Tonight we will go out for dinner.
Tonight, we will go out for dinner.
However, if omitting the comma causes confusion, include it.
❌ Confusing:
Before eating the guests washed their hands.
✅ Clear:
Before eating, the guests washed their hands.
Common Types of Introductory Phrases
1️⃣ Prepositional Phrases (Indicating Time, Place, or Manner)
- At the park, children played happily.
- During the storm, the power went out.
2️⃣ Participial Phrases (Starting with an -ing or -ed Verb Form)
- Walking through the forest, we saw a deer.
- Excited about the trip, she packed her bags early.
3️⃣ Infinitive Phrases (Starting with “To” + Verb)
- To finish the project, we worked late into the night.
- To succeed, you must work hard.
4️⃣ Transitional Words and Phrases
- However, we still need to finalize the details.
- On the other hand, she had a different opinion.
What Happens If You Skip the Comma?
Omitting the comma can sometimes cause confusion or make the sentence harder to read.
❌ Incorrect:
Before sleeping I like to read.
✅ Fixed:
Before sleeping, I like to read.
❌ Incorrect:
While cooking the kids played in the living room.
✅ Fixed:
While cooking, the kids played in the living room.
(Without the comma, it sounds like the kids were cooking!)
6. Commas with interrupters or parenthetical elements
Interrupters and parenthetical elements are words or phrases that break the flow of a sentence to add emphasis, commentary, or extra details. To maintain clarity and readability, these elements should be set apart with commas.
Rule: Use Commas to Set Off Interrupters and Parenthetical Elements
✅ Correct Example:
This book, in my opinion, is a must-read.
(The phrase “in my opinion” interrupts the main sentence and adds a personal thought.)
✅ Correct Example:
The project, as you might expect, took longer than planned.
(The phrase “as you might expect” adds commentary.)
✅ Correct Example:
He was, without a doubt, the best player on the team.
(“Without a doubt” is an interrupter that adds emphasis.)
What Are Interrupters and Parenthetical Elements?
Interrupters
Interrupters are words or phrases that break the sentence’s flow to add emphasis or a side comment.
- Common interrupters:
- of course
- however
- in fact
- nevertheless
- on the other hand
- to be honest
- surprisingly
✅ Examples:
- She will, of course, be attending the meeting.
- The food was, surprisingly, quite good.
Parenthetical Elements
These provide extra, nonessential information that could be removed without changing the core meaning of the sentence.
✅ Examples:
- My brother, who just graduated college, is looking for a job.
- The movie, which was released last year, became an instant hit.
- Our teacher, Mrs. Johnson, gave us an extra day for the assignment.
What Happens If You Skip the Commas?
Leaving out commas can make the sentence confusing or difficult to read.
❌ Incorrect:
The answer however is not so simple.
✅ Fixed:
The answer, however, is not so simple.
❌ Incorrect:
The new store which opened last week has great discounts.
✅ Fixed:
The new store, which opened last week, has great discounts.
(Without commas, “which opened last week” sounds like an essential part of the sentence, but it’s just extra information.)
7. Commas with Question Tags
A question tag is a short phrase added at the end of a statement to turn it into a question. It is often used to confirm information, seek agreement, or encourage a response. To properly set apart a question tag, use a comma before it.
Rule: Use a Comma Before a Question Tag
When adding a question tag to a statement, place a comma before the tag to separate it from the main sentence.
✅ Correct Example:
You’re coming to the party, aren’t you?
✅ Correct Example:
It’s a beautiful day, isn’t it?
✅ Correct Example:
She can play the guitar, can’t she?
(The comma helps separate the main statement from the tag, making the sentence clearer.)
What Happens If You Skip the Comma?
Without a comma, the sentence may feel rushed or harder to read.
❌ Incorrect:
You like pizza don’t you?
✅ Fixed:
You like pizza, don’t you?
❌ Incorrect:
He will be there won’t he?
✅ Fixed:
He will be there, won’t he?
Common Question Tags
Question tags usually match the subject and auxiliary verb of the main sentence. Here are some common examples:
🔹 Positive Statement → Negative Question Tag
- She is a teacher, isn’t she?
- They have finished, haven’t they?
- You like coffee, don’t you?
🔹 Negative Statement → Positive Question Tag
- He isn’t coming, is he?
- You don’t eat meat, do you?
- They haven’t left yet, have they?
🔹 With Modal Verbs (can, will, should, etc.)
- She can swim, can’t she?
- We should leave now, shouldn’t we?
- He won’t be late, will he?
8. Commas with Direct Address
When addressing someone directly in a sentence, their name or title should be set apart with commas. This helps clarify the meaning and ensures that the sentence reads smoothly.
Rule: Use Commas to Set Off Names in Direct Address
Whenever you speak to someone and mention their name, place commas around the name or title to separate it from the rest of the sentence.
✅ Correct Example (At the Beginning):
Emma, can you help me with this project?
✅ Correct Example (In the Middle):
I think, Sarah, you will love this book.
✅ Correct Example (At the End):
That was an amazing performance, John.
(The commas make it clear that the speaker is addressing someone directly.)
What Happens If You Skip the Comma?
Leaving out commas can completely change the meaning of a sentence.
❌ Incorrect:
Let’s eat Grandpa! (This sounds like Grandpa is on the menu!)
✅ Fixed:
Let’s eat, Grandpa! (Now it’s clear that Grandpa is being invited to eat.)
❌ Incorrect:
I know Alice is smart. (This suggests that the speaker knows that Alice is smart.)
✅ Fixed:
I know, Alice, is smart. (Now the speaker is talking to Alice and stating that someone else is smart.)
When to Use Commas with Titles in Direct Address
If you’re addressing someone by their title, use commas the same way.
✅ Examples:
- Good morning, Dr. Smith.
- Can you help me, officer?
- Thank you for your time, Mr. President.
However, if you’re not directly addressing the person, don’t use commas.
❌ Incorrect:
The doctor, Smith, will see you now. (This suggests “Smith” is extra information.)
✅ Fixed:
The doctor Smith will see you now. (No comma because “Smith” is necessary to identify which doctor.)
9. Commas with dates
When writing dates, commas are used to separate certain elements to improve clarity and readability. The placement of commas depends on the format used.
Rule 1: Use a Comma Between the Day and the Year
When writing the month, day, and year, a comma should separate the day from the year.
✅ Correct Example:
August 15, 2025, is our wedding anniversary.
✅ Correct Example:
The event took place on March 22, 1998, in New York.
(The comma after the year is necessary if the sentence continues.)
❌ Incorrect:
We met on December 5 2010 at the café.
✅ Fixed:
We met on December 5, 2010, at the café.
Rule 2: No Comma When Only the Month and Year Are Mentioned
If you write only the month and year, no comma is needed.
✅ Correct Example:
We moved to the city in April 2020.
❌ Incorrect:
We moved in April, 2020.
(There should be no comma between “April” and “2020.”)
Rule 3: Use a Comma After the Year When It Appears Mid-Sentence
If the date appears in the middle of a sentence, place a comma after the year as well.
✅ Correct Example:
On July 4, 1776, the Declaration of Independence was signed.
✅ Correct Example:
Our graduation on May 30, 2023, will be unforgettable.
❌ Incorrect:
On July 4, 1776 the Declaration of Independence was signed.
✅ Fixed:
On July 4, 1776, the Declaration of Independence was signed.
Rule 4: No Comma in the Day-Month-Year Format
In the day-month-year format (common outside the U.S.), no commas are needed.
✅ Correct Example (British/International Style):
The meeting is on 12 September 2022.
❌ Incorrect:
The meeting is on 12 September, 2022.
(No comma is needed in this format.)
Rule 5: Use a Comma When a Day of the Week is Included
If a date starts with a day of the week, place a comma after the day and the year.
✅ Correct Example:
Monday, June 5, 2023, was a great day.
✅ Correct Example:
Saturday, December 25, 2021, was very special.
10. Commas with Locations
When writing locations, commas are used to separate different parts, such as the city and country, city and state, or district and country. This helps improve readability and clarity.
Rule 1: Use a Comma Between a City and Its State or Country
When listing a city and a state (or city and country), always place a comma between them.
✅ Correct Example:
I visited Paris, France, last summer.
✅ Correct Example:
She grew up in Austin, Texas.
✅ Correct Example:
They are moving to London, England, next year.
❌ Incorrect:
We traveled to Cairo Egypt for our honeymoon.
✅ Fixed:
We traveled to Cairo, Egypt, for our honeymoon.
Rule 2: Use a Comma After the State or Country If the Sentence Continues
If the location appears mid-sentence, add a comma after the state or country as well.
✅ Correct Example:
My cousin lives in Denver, Colorado, and she loves it there.
✅ Correct Example:
He moved to Tokyo, Japan, for work.
❌ Incorrect:
We visited Rome, Italy last summer.
✅ Fixed:
We visited Rome, Italy, last summer.
Rule 3: No Comma When Only the State or Country Is Mentioned
If you’re mentioning just the state or country (without a city), no comma is needed.
✅ Correct Example:
We are traveling to Canada this fall.
✅ Correct Example:
I grew up in California.
❌ Incorrect:
We are traveling to, Canada, this fall.
✅ Fixed:
We are traveling to Canada this fall.
Rule 4: Use a Comma When Listing Multiple Locations
When listing multiple locations, use commas between each.
✅ Correct Example:
Our trip included stops in New York, New York; Chicago, Illinois; and Miami, Florida.
✅ Correct Example:
She has lived in Berlin, Germany; Madrid, Spain; and Lisbon, Portugal over the past five years.
(Notice how a semicolon (;) is used when locations include commas to avoid confusion.)
11. Commas with coordinate adjectives
When using multiple adjectives to describe a noun, commas are sometimes needed to separate them. The key is knowing when adjectives are coordinating and when they are cumulative—because only coordinating adjectives need commas.
Rule: Use a Comma Between Coordinating Adjectives
Coordinating adjectives are adjectives that equally describe a noun and can be rearranged without changing the meaning. If the adjectives are coordinating, separate them with a comma.
✅ Correct Example:
It was a cold, windy night.
(You can say “windy, cold” night, and it still makes sense.)
✅ Correct Example:
They adopted a playful, energetic puppy.
(You can say “energetic, playful” puppy, and it still sounds right.)
✅ Correct Example:
He is a smart, talented musician.
(“Talented, smart” musician also works.)
How to Test If Adjectives Need a Comma
Use these two simple tests:
1️⃣ Swap the adjectives: If switching their order doesn’t change the meaning, they are coordinating, and a comma is needed.
2️⃣ Insert “and” between them: If the sentence still makes sense, they are coordinating, and a comma is needed.
🔹 Example:
“She wore a bright, colorful dress.”
- Swap test: “She wore a colorful, bright dress.” ✅ (Makes sense)
- “And” test: “She wore a bright and colorful dress.” ✅ (Still makes sense)
Since both tests work, a comma is needed.
When NOT to Use a Comma: Cumulative Adjectives
Cumulative adjectives build upon each other, meaning they must stay in order and cannot be separated by a comma.
✅ Correct Example:
She bought a dark blue dress.
(You wouldn’t say “blue dark dress,” so no comma is needed.)
✅ Correct Example:
He drives a large wooden boat.
(You wouldn’t say “wooden large boat,” so no comma.)
✅ Correct Example:
It was a delicious chocolate cake.
(You wouldn’t say “chocolate delicious cake,” so no comma.)
12. Quotations and Attributive Tags
When writing dialogue or incorporating quotes, commas are used to separate the quotation from the attributive tag (the part that tells who is speaking). Proper punctuation makes sentences clearer and easier to read.
Rule 1: Use a Comma to Separate an Introductory Attributive Tag from a Quotation
When the attributive tag (speaker tag) comes before the quote, use a comma after the tag and before the opening quotation marks.
✅ Correct Example:
She said, “I love reading mystery novels.”
✅ Correct Example:
He whispered, “Be careful!”
✅ Correct Example:
The teacher explained, “We will have a quiz tomorrow.”
❌ Incorrect:
He said “Let’s go to the park.”
✅ Fixed:
He said, “Let’s go to the park.”
Rule 2: Use a Comma When the Attributive Tag Comes After the Quotation
When the attributive tag comes after the quote, place a comma inside the closing quotation marks, before the tag.
✅ Correct Example:
“This is my favorite song,“ she said.
✅ Correct Example:
“I can’t believe it,“ he muttered.
✅ Correct Example:
“We should leave now,“ John insisted.
❌ Incorrect:
“This is amazing” she said.
✅ Fixed:
“This is amazing,“ she said.
Note: If the quote ends with a question mark or exclamation point, do NOT use a comma. Instead, just use the punctuation mark and continue with a lowercase attributive tag.
✅ Correct Example:
“Are you coming?”** she asked.
“Watch out!”** he shouted.
❌ Incorrect:
“Are you coming?,“ she asked.
“Watch out!,“ he shouted.
Rule 3: Use a Comma When the Attributive Tag Interrupts the Quotation
If the attributive tag appears in the middle of a quote, place a comma inside the first closing quotation marks and another after the tag before continuing the quote.
✅ Correct Example:
“I don’t know,“ she said, “if we should go.”
✅ Correct Example:
“This is amazing,“ he whispered, “but we have to be quiet.”
❌ Incorrect:
“This is amazing” he whispered, “but we have to be quiet.”
✅ Fixed:
“This is amazing,“ he whispered, “but we have to be quiet.”
📌 Note: If the second part of the quote starts a new sentence, capitalize the first letter.
✅ Correct Example:
“This is incredible,“ she said. “We should tell everyone!”
13. Commas with “as well as”
Rule: Use commas when “as well as” introduces extra, nonessential information but NOT when it’s essential to the meaning of the sentence.
✅ With Commas (Nonessential Information):
My brother, as well as my sister, loves hiking.
(“As well as my sister” is extra information and can be removed without changing the sentence’s core meaning.)
✅ With Commas (Interruption):
The project, as well as the budget proposal, needs approval.
(The phrase is additional information, so commas are needed.)
❌ No Comma (Essential to the Meaning):
Employees as well as managers must follow the new policy.
(Here, “as well as managers” is essential to the meaning, so no commas are needed.)
Test: If the phrase can be removed without changing the main idea, use commas. If removing it changes the meaning, do not use commas.
14. Commas with “such”
Rule: Use commas when “such” introduces an example (such as) but NOT when it’s part of a phrase like “such a” or “such that.”
✅ With Commas (Introducing Examples with “such as”)
You should eat more fruits, such as apples and bananas.
(“Such as apples and bananas” provides an example, so a comma is needed before it.)
✅ With Commas (Interrupting a Sentence)
Certain animals, such as lions and tigers, are carnivorous.
(The phrase is nonessential, so commas are used.)
❌ No Comma (Part of a Phrase)
It was such a beautiful day that we decided to go out.
(No comma because “such a” is a fixed phrase.)
❌ No Comma (Cause-Effect Structure)
The situation was such that we had no choice but to leave.
(No comma because “such that” connects the cause and effect.)
Test: If “such as” introduces examples, use a comma before it. If “such” is part of a phrase, do not use a comma.
15. Commas with “too”
Rule: Use a comma when “too” means “also” and appears at the end or middle of a sentence, but NOT when it appears in the middle without interrupting the flow.
✅ With a Comma (At the End of a Sentence)
I love chocolate, too.
(“Too” adds additional information and is set off with a comma.)
✅ With a Comma (Interruption)
She, too, was surprised by the results.
(“Too” interrupts the sentence, so commas are used.)
❌ No Comma (No Interruption)
She was too tired to continue.
(Here, “too” means “very” rather than “also,” so no comma is needed.)
Test: If “too” is removable without changing the meaning, use a comma. If “too” is part of a phrase, don’t use a comma.
Places Where a Comma Should (Almost) Never Appear
While commas help improve clarity and readability, there are certain places in a sentence where a comma should (almost) never be used. Misplacing a comma in these situations can lead to incorrect or awkward sentence structure. Let’s go over the rules, examples, and common mistakes to avoid.
Between Subjects and Verbs
Rule: Never place a comma between the subject and the verb in a sentence.
❌ Incorrect:
The cat, sleeps on the windowsill.
✅ Correct:
The cat sleeps on the windowsill.
❌ Incorrect:
The new policy, will take effect next month.
✅ Correct:
The new policy will take effect next month.
Exception: If a nonessential phrase appears between the subject and the verb, commas may be necessary.
✅ Correct Example:
My brother, who lives in Canada, is visiting next week.
In Compound Subjects or Objects
Rule: Do not place a comma between two parts of a compound subject or compound object.
❌ Incorrect:
My parents, and my sister are coming to visit.
✅ Correct:
My parents and my sister are coming to visit.
❌ Incorrect:
She bought apples, and oranges at the market.
✅ Correct:
She bought apples and oranges at the market.
Exception: If the list contains three or more items, then a comma is appropriate before the final conjunction (optional Oxford comma).
✅ Correct Example:
She bought apples, oranges, and bananas.
In Compound Predicates (Two or More Verbs for the Same Subject)
Rule: Do not place a comma between two verbs that share the same subject.
❌ Incorrect:
He finished his homework, and went to bed.
✅ Correct:
He finished his homework and went to bed.
❌ Incorrect:
The dog barked, and ran across the yard.
✅ Correct:
The dog barked and ran across the yard.
Exception: If the second part of the predicate is long or introduces a contrast, a comma may be acceptable for clarity.
✅ Correct Example:
She finished her book, and then decided to start a new one with a different genre.
Between Verbs and Their Objects
Never place a comma between a verb and its direct object or complement.
❌ Incorrect:
She enjoys, painting and drawing.
✅ Correct:
She enjoys painting and drawing.
❌ Incorrect:
The teacher explained, the new concept in detail.
✅ Correct:
The teacher explained the new concept in detail.
With Correlative Conjunctions (Either…or, Neither…nor, Not only…but also, Both…and, etc.)
Rule: Do not separate the parts of correlative conjunctions with a comma.
❌ Incorrect:
Either, you finish your work or you fail the assignment.
✅ Correct:
Either you finish your work or you fail the assignment.
❌ Incorrect:
Both, my brother and my cousin are attending the wedding.
✅ Correct:
Both my brother and my cousin are attending the wedding.
Exception: A comma may be needed for clarity if a nonessential clause is inserted.
✅ Correct Example:
Either my brother, who is an engineer, will help us, or we’ll hire a professional.
Between Articles and Nouns
Rule: Do not place a comma between an article (a, an, the) and the noun it modifies.
❌ Incorrect:
He adopted a, puppy from the shelter.
✅ Correct:
He adopted a puppy from the shelter.
❌ Incorrect:
They visited the, museum on Sunday.
✅ Correct:
They visited the museum on Sunday.
With “Than” in Comparisons
Rule: Do not place a comma before or after “than” in comparisons.
❌ Incorrect:
She runs faster, than her brother.
✅ Correct:
She runs faster than her brother.
❌ Incorrect:
This book is more interesting, than the one I read last week.
✅ Correct:
This book is more interesting than the one I read last week.
Exception: If a nonessential phrase follows “than,” a comma may be used.
✅ Correct Example:
She is taller than, I had expected, by at least two inches.