Other Uses of Commas

Other Uses of Commas to Consider

Numbers

Use a comma to separate the thousands place in a numeral.

Example: 1,000
Example: 30,000
Example: 999,999,999

Remember that different style guides have different rules on when to use a numeral and when to use the word form of a number (in other words, 10 instead of ten).

Place-names

Use commas to separate place-name elements from each other. A place-name element is a location name like a street address, city, state, country, or campus.

Example: I visited my friend in Atlanta, Georgia, a few days ago.
Example: I visited my friend in Paris, France, a few years ago.
Example: Pittsburgh, PA, is home to some of the nation’s largest steel mills.
Example: I presented at a conference at the University of South Florida, Tampa, on the topic of sustainability.

When multiple place-names are listed together in a sentence, a comma should come after the last place-name element, unless it is the last word in the sentence.

Example: I went to the campus bookstore at 2727 Mansfield Blvd., Wesley Chapel, Florida, to purchase textbooks for my class.

Do not use a comma if there is only one place-name.

I visited my friend in Atlanta a few days ago.
I presented at a conference at the University of South Florida on the topic of sustainability.
I went to the campus bookstore at 2727 Mansfield Blvd. to purchase textbooks for my class.

No matter which style guide you are following, the numbers in a place-name should be represented by numerals.

Dates

Use a comma for dates expressed in month-day-year format. When this date format is used in a sentence, a comma should come after the year, unless it is the last word in the sentence.

Example: Comic book writer Stan Lee was born on December 28, 1922, and died on November 12, 2018.

Do not use a comma for dates expressed in day-month-year format.

Example: Comic book writer Stan Lee was born on 28 December 1922 and died on 12 November 2018.

When using a month and a year in a sentence or a season and a year in a sentence, do not separate the elements of the date with a comma.

The so-called "Y2K bug” that was supposed to cripple computer systems on January 2000 was vastly overblown.
I graduated at the end of spring 2022.

No matter which style guide you are following, the numbers in a date should be represented by numerals.

Separating signal phrases from sentence quotes

A signal phrase identifies who is speaking when a quote is used in a sentence. Use commas to separate signal phrases from their quotes.

If a signal phrase comes after a quote, place the comma before the end quotation mark.

Example: “There will be an earthquake along the Santa Barbara fault within the next ten years,” according to Morelli.

If a signal phrase comes before a quote, place the comma before the first quotation mark.

Example: According to Morelli, “There will be an earthquake along the Santa Barbara fault within the next ten years.”

If a signal phrase interrupts a single quoted sentence, follow both of the rules above.

Example: “There will be an earthquake,” according to Morelli, “along the Santa Barbara fault line within the next ten years.”