Punctuation - Comma Rules

The main rule for the use of commas in English is: Keep your sentences clear. Too many commas might be distracting; too few might make the text difficult to read and understand.

Always check your texts on readability. This requires some practice, however, as first you must know which commas are necessary and which are optional.

The following chapters contain explanations on English comma rules. In our exercises you can practise what you've learned.

1-Commas with Numbers:

Use commas to separate off the thousands and millions in compound numbers.

Example: 3,460,759

Don’t use commas in decimals.

Example: $3.49

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

Example: April 16, 2003

2-Commas with Salutations:

Use a comma if the sentence starts with an address to someone.

Example: Greg, can I talk to you for a second?

Use a comma with salutations in private letters.

Example: Dear Francis,

Don’t use a comma with salutations in business letters. Use a colon in American English and no punctuation mark in British English.

Example: BE – Dear Mr Jefferson   -AE – Dear Mr. Jefferson:

After the greeting, the comma is optional.

Example: Sincerely, Sincerely

3-Commas with Geographic Places:

Use a comma to separate parts of geographic places. The final comma is optional.

Example: Hollywood, Ireland(,) is not as famous as Hollywood, California.

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

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

4-Commas with Adjectives:

Use a comma if the adjectives are equally important and give similar kinds of information.

Example: It was a cold, windy morning.

Don’t use a comma if the adjectives are not equally important or give different kinds of information.

Example: He was a clever young man.

5-Commas with Adverbs:

Use a comma after certain adverbs: however, in fact, therefore, nevertheless, moreover, furthermore, still, instead, too (meaning 'also').

Example: Therefore, he didn't say a word.

If these adverbs appear in the middle of a sentence, they are enclosed in commas.

Example: The thief, however, was very clever.

The comma is optional for the following adverbs: then, so, yet.

Example:
 So, she entered the house.
 So she entered the house.

6-Commas with Enumerations:

Use a comma to separate items in an enumeration.

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.

Don’t use a comma before “and” if two items are 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 all items in an enumeration are separated by “and”, “or”, “nor” etc.

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

7-Commas with Direct Speech:

Use a comma after the introductory clause.

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

If 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 the direct speech 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!”)