Comma

Commas in English

The main use for commas in English is to keep your sentences clear. Too many commas may be distracting, too few may make the text difficult to read and understand. Always check your texts for readability. This requires some practice, however, as first you must know which commas are necessary and which are optional. Click on the tabs below to learn about the different uses of commas in English.

Content

Commas and Coordinating Conjunctions

A comma is usually optional when two main clauses are connected by a coordinating conjunction (and, but, or, so, nor, for, yet), and we often omit the comma when the clauses share the same subject.

Example:
We ran out of petrol[,] and got lost trying to find help.
The breakdown service was helpful[,] but they didn’t arrive for hours.

If the main clauses are particularly short, we omit the comma.

Example:
We had two choices: try to find help or stay with the car.

We use a comma when the coordinating conjunctions connect two independent clauses. This is when the clauses can act as stand alone sentences, or when the clauses have two different subjects.

Example:
I tried calling the breakdown service, but they didn’t answer immediately.
The mechanic said that the car can’t be repaired, so I guess we are going car shopping next week.

We don‘t use a comma when the coordinating conjunctions are used to separate two objects or elements in a sentence.

Example:
Luckily we had food and water while we waited.
Now we have to take the bus or the tram.

Complex Sentences

Use a comma, in complex sentences, to separate a dependent clause followed by a main clause.

Example:
After I fed the cat, I washed my hands.
Before she goes to bed, Judy always brushes her teeth.
In order to tie his shoelaces, he stopped walking.
If I go to London, I’ll visit the Tower.

However, when a main clause is followed by a dependent clause, no comma is needed.

Example:
I washed my hands after I fed the cat.
Judy always brushes her teeth before she goes to bed.
He stopped walking in order to tie his shoelaces.
I’ll visit the Tower if I go to London.

For more information about syntax in English grammar see word order.

Opposites

Use a comma with opposites, even if they are separated by and or but.

Example:
It was the father, and not the son, who went to the disco every Friday.

Relative Clauses

Use commas before the relative pronouns who and which in non defining relative clauses. The commas here indicate that the information given is not essential.

Example:
Her brother, who lives in Chicago, came to see her.

She has only one brother. He lives in Chicago and came to see her.

My next door neighbour, who has a beautiful garden, is a dentist.

I have only one next door neighbour. She is a dentist and has a beautiful garden.

Don’t use commas in defining relative clauses. This is because the information given here is essential.

Example:
Her brother who lives in Chicago came to see her.

She has more than one brother, and the one who lives in Chicago came to see her.

My next door neighbour who has a beautiful garden is a dentist.

I have more than one next door neighbour, and the one who has a beautiful garden is a dentist.

Don’t use commas before the relative pronoun that.

Example:
The book that I’m reading is interesting.
Where are the eggs that were in the fridge?

For more information see relative clauses in the sentences section of the website.

Introductory Phrases and Words

Use a comma after introductory clauses. They can be infinitive, prepositional or participle clauses.

Example:
To improve her English, she practised on Lingolía every day. (infinitive phrase)
Before he went to New York, he had spent a year in Australia. (prepositional phrase)
Having said this, he left the room. (participle phrase)
Well, maybe it was an accident. (introductory word)

Use a comma after introductory words and phrases that come before main clauses. Common introductory words include yes, well and however.

Example:
Well, maybe it was an accident. (introductory word)
By the way, my name is Mike not Mickey. (introductory phrase)
A long time ago, dinosaurs walked the earth. (introductory phrase)

Additional Information

Use two commas to separate additional information, phrases, clauses and words, that are not essential to the meaning of the sentence.

Example:
Thank you, ladies and gentlemen, for giving me the opportunity to speak to you today.
We were, believe it or not, in love.
My mother, however, did not agree.
Next Saturday, which is my sister’s birthday, is the only day I’m available to see you.

Info

Depending on the importance attached to it, additional information can be enclosed in brackets, commas or dashes.

Brackets – not important

Example:
Connor (Amy's boyfriend) bought the tickets.

Commas – neutral

Example:
Connor, Amy's boyfriend, bought the tickets.

Dashes – emphasised

Example:
Connor – Amy's boyfriend – bought the tickets.

Use commas in in non-defining relative clauses.

Example:
The couch, which is very comfortable, is yellow.

Don’t use commas in defining relative clauses or before that.

Example:
His daughter who is five just started school.

He has more than one daughter.

The book that I’m reading is very interesting.

For information about other punctuation marks for additional information see brackets and dashes in the writing school section of the website.

Direct Speech

Use a comma after the introductory clause.

Example:
She said, “I was in London last year.”

When the direct speech is at the beginning of the sentence, put the comma before the final quotation mark. (Don’t use a full stop here.)

Example:
“I was in London last year,” she said.

Don’t use a comma after direct speech if it ends with a question mark or exclamation mark.

Example:
“Were you in London last year?” he asked. (but: He asked, “Were you in London last year?”)
“Great!” she replied. (but: She replied, “Great!”)

For more information about the use of quotation marks in English grammar see quotation marks.

Question tags

Use a comma before question tags.

Example:
You are Scottish, aren’t you?
She lives in Toronto, doesn’t she?

Commas with Yes/No

Use a comma after yes and no.

Example:
Yes, I can help you.
No, he’s not here at the moment.

Commas with Please

Use a comma before please at the end of a request.

Example:
Send me an email, please.
Can you return the library books, please?

A comma is not usually used when please is at the beginning of a request.

Example:
Please send me an email.
Please clean your room.

However, you can use a comma after please at the beginning of a request to add emphasis.

Example:
Please, don't forget to send me that email.
Please, return those library books as soon as possible.

Lists

Use a comma to separate items in a list.

Example:
Old McDonald had a pig, a dog, a cow, a horse.

The comma before and is optional. Choose the option you like best and stick to it.

Example:
Old McDonald had a pig, a dog, a cow and a horse.
Old McDonald had a pig, a dog, a cow, and a horse.

Info

Use a comma before and to avoid ambiguity.

Example:
She thanked her parents, Mark and Luisa.

Did she thank four people? Or did she thank her parents whose names are Mark and Luisa? The meaning is not clear, perhaps her father's name is Mark.

She thanked her parents, Mark, and Luisa.

She thanked four people.The meaning here is clear.

Don’t use a comma before and if two items form a unit (“ham and eggs” as a dish is a unit and should therefore not be separated by a comma).

Example:
Old McDonald had soup, ham and eggs and apple pie for dinner.
Old McDonald had soup, ham and eggs, and apple pie for dinner.

Don’t use a comma if the items in a list are separated by and, or, nor etc.

Example:
Old McDonald had a pig and a dog and a cow and a horse.
Did Old McDonald have a pig or a dog or a cow or a horse?
Old McDonald neither had a pig nor a dog nor a cow nor a horse.

For more information about the conjunctions and, or, nor go to conjunctions in the sentences section of the website. Check out brackets, colon and semicolon to find out more about punctuation in lists.

Conjunctive Adverbs

Use a comma after conjunctive adverbs such as: however, in fact, therefore, nevertheless, moreover, furthermore, still, instead.

Example:
Therefore, he didnt say a word.
In fact, Mary had never been to Spain.
Still, I wasn’t sure if I believed him.

If the adverb appears in the middle of the sentence, use two commas. One before and one after.

Example:
The thief, however, was very clever.
Mary had, in fact, never been to Spain.

The use of a comma is optional after then, so, too and yet.

Example:
So, she entered the house.
So she entered the house.
It wasn’t dark, yet.
It wasn’t dark yet.
He needed to go to the dentist, too.
He needed to go to the dentist too.

Adjectives

Coordinate Adjectives

Use commas to separate coordinate adjectives that modify the same noun. Coordinate adjectives describe the same qualities of the noun in question.

Example:
A wet, cold, windy morning.

In this example, wet, cold and windy describe the weather.

Samantha thinks that the Mona Lisa is a weird, ugly painting.

In this example, weird and ugly both describe her opinion of the painting.

I was driving down a slippery, wet road.

In this example, slippery and wet describe the feel of the road.

She is a friendly, open-minded person.

In this example, friendly and open-minded both describe the personality of the person.

Info

For native speakers, it's easy to test if adjectives are coordinate or not. Adjectives are coordinate if

  • the order of the adjectives can be reversed without changing the meaning
    Example:
    a cold, wet, windy morning
  • and can be placed in between the adjectives
    Example:
    I was driving down a slippery and wet road.

Cumulative Adjectives

Don’t use commas if the adjectives are cumulative. This is because the last adjective and the noun form a unit which is then modified by the previous adjectives.

Example:
He was a clever young man.

In this example, young + man form one unit which is then modified by clever.

She wore a white silk scarf.

In this example, silk + scarf form a unit which is then modified by white.

The school has hard old wooden chairs.

In the example, wooden + chairs form a unit which is modified by hard and old.

Cumulative adjectives usually follow a specific order.

Observation Size and Shape Age Colour Origin Material Purpose Noun
tall 30-year-old American woman
beautiful big new yellow Italian canvas beach bag
strange gold woollen evening gown

If the order of the adjectives is changed or if two adjectives belong to the same category, a comma must be used.

Example:
a big, tall building

Info

Don’t use a comma between an adjective and a noun or an adverb and an adjective.

Example:
My cousin is a published writer.
Her house was wonderfully clean.

To learn more about punctuation and adjectives see hyphen.

Salutations and Valedicitions

Use commas with a person’s name or title when directly addressing them.

Example:
Greg, can I talk to you for a second?
Thank you, Doctor, for all of your help.

Use a comma with salutations in private letters.

Example:
Dear Francis,

In British English, the use of commas with salutations in business letters is optional. Use a colon in American English.

Example:
BE → Dear Mr Jefferson
BE → Dear Mr Jefferson,
AE → Dear Mr. Jefferson:

After the valediction, the comma is optional.

Example:
Sincerely,
Sincerely

Info: Consistency is The Key

Consistency is important in all forms of written communication. If a comma has not been used after the salutation, don’t use a comma after the valediction. If a comma has been used after the salutation, use a comma in the valediction.

Example:
Dear Ms Mathews
Sincerely
Dear Mr Jefferson,
Sincerely,

Names

Use a comma when writing names surname first, or before titles that follow a name.

Example:
Smith, John
Lisa Jones, Ph.D.

Geographical Names and Addresses

Use a comma to separate parts of geographical names such as cities, states and countries. The final comma is optional.

Example:
Hollywood, Ireland(,) is not as famous as Hollywood, California.
She comes from Melbourne, Australia.
Dallas, Texas(,) is in the USA.

Use a comma to separate parts of an address in a sentence.

Example:
His address is 46 Baker Street, London, NW2 2LK, Great Britain.

Numbers

Use commas to separate thousands and millions.

Example:
4,182
3,460,759

Use a decimal point (and not a comma) to separate dollars and cents or decimals.

Example:
$3.49

Use a comma before the year if the date is given as follows: month/day/year.

Example:
April 16, 2014

Don’t use a comma if only two elements of the date are given (e.g. month and year).

Example:
I was born in May 1972.

See numbers, dates and time for more information.

Readability

Commas help to keep the structure of the sentence clear so that the text is easy to read and understand. A text is well structured when the reader knows where to pause.

Example:
Above, the eagle flew gracefully through the air.

Info

Without the comma, the sentence might be confusing for the reader as the first three words can be seen as a unit (“Above the eagle …”). Of course, the sentence does not work this way, but the reader might have to read the sentence again to get the message. By using a comma after “above”, the author makes the sentence easier to read and understand.