How to use Commas

Comma

A comma in writing is a like a pause inside a sentence when speaking. We use commas inside sentences. Commas separate parts of a sentence into logical elements. Commas have no meaning, but they help us to see the structure and therefore the meaning of the sentence.

Put a space after a comma. Do not put a space before a comma.

xxx, xxx correct
xxx ,xxx incorrect
xxx , xxx

1. Use a comma between items in a series or list. In a sentence, the last two items usually do not need a comma between them as they are separated by "and". However, if one or both of the last two items are long, a comma may be useful.

coffee, tea, sugar, milk, eggs, butter, salt
My favourite sports are football, rugby, swimming, boxing and golf.
Hunsa was wearing blue jeans, black shoes, his brand new white shirt, and a brown and green cap.
2. Use a comma between three or more adjectives or adverbs.

I like the old, brown, wooden table.
He bought an old, red, open-top Volkswagen.
He ran quickly, quietly and effortlessly.
3. For two adjectives, use a comma where you could use "and".

It was a short, simple film. (It was a short and simple film.)
I have a big black dog. (I have a big and black dog.)
4. Use a comma for numbers over 999. (In English, commas separate thousands and periods separate decimals. Note that some languages use the opposite system.)

1,000 (one thousand)
1,569
$73,050.75
2,000,000
3,400,500
10.5 (ten and a half) - note the use of the period, not comma
5. Use a comma for addresses, some dates, and titles following a name.

911 Avenue Mansion, Petchburi Road, Bangkok, 10400, Thailand
Los Angeles, California
November 4, 1948 (but 4 November 1948)
Fred Ling, Professor of English
6. Use a comma before or after direct speech. Do not use a comma for reported speech.

He said, "I love you."
"I love you," he said.
He told her that he loved her.
7. Use a comma before a coordinating conjunction (for, and, nor, but, or, yet, so) to join two independent clauses. If the independent clauses are short and well-balanced, a comma is optional.

He didn't want to go, but he went anyway.
I want to work as an interpreter, so I am studying Russian at university.
She is kind so she helps people.
8. Use commas for parenthetical elements. A "parenthetical element" is any part of a sentence that can be removed without changing the real meaning of the sentence.

John Geton, who is chairman of the company, is quite old.
Andrew, my wife's brother, cannot come.
Andrew (my wife's brother) cannot come.
The objective, to find peace in both countries, is hard to reach.
9. Use a comma after an introductory element. A comma is optional for short, simple introductory elements.

Rushing to catch the flight, he forgot to take his phone.
As the year came to an end, he realised the days were getting shorter.
By evening we were getting worried.
After a hefty meal cooked by his host's wife, he went to sleep.
After a snack he went to sleep.
10. Sentence adverbs (words like however, unfortunately, surprisingly that modify a whole sentence) often require one or two commas, depending on their position in the sentence.

However, Anthony did arrive.
Anthony, however, did arrive.
We were, unfortunately, too late.
He had, not surprisingly, lost his temper.
11. An adverbial clause often needs a comma when it comes at the beginning of a sentence (but not at the end of a sentence).

If I win the lottery, I will buy a castle.
I will buy a castle if I win the lottery.
12. Do not use a comma to separate two complete sentences. In this case, use a full stop (period) or semi-colon.

Ram wants to go out. Anthony wants to stay home.
Ram wants to go out, Anthony wants to stay home.
Tara, Ram and Anthony enjoyed their holiday, which they spent in Rio Claro, Trinidad, from December 17, 2010 to January 6, 2011. Unfortunately, although the weather was good, if rather hot, it rained a lot during their last week. Ravi, Tara's uncle, said, "When I was young we had very little rain, but now we have a lot of rain." Ravi, a wealthy, good-looking man, lives in the north of the island.
"I have spent most of the day putting in a comma and the rest of the day taking it out. "
Oscar Wilde