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COMMA USAGE

Between Independent Clauses: (IC)          

When the independent clauses in a sentence are joined by a coordinating conjunction (and, but, or, or nor) use a comma to separate them.  Note that the comma precedes the conjunction.

The company has an office in Racine, and it is planning to open another in Eau Claire.

We think that a decision has been reached, but we do not know when it will be announced.

If the independent clauses are very short and very closely related, do not use a comma to separate them.

            The carpet is beige and the drapes are brown.

In a Series: (SER)     

Unless all the items are joined by conjunctions, use a comma after all but the last item in a series of three or more items.

She will be out of the office on Monday, Tuesday, and Friday of next week.

But:  I am not sure whether Lorraine is in Ohio or Pennsylvania or Indiana.

When the series ends with etc., and so on, or a similar expression, use a comma before and after the expression.  If the expression occurs at the end of a sentence, no comma follows it, of course. 

Note: Never use and with etc. (Etc. is the abbreviation of et cetera, which means “and so forth.”)

          You will find pens, pencils, notebooks, etc., in the stockroom.

          Tables, lamps, chairs, and so on, will be on sale next week.

But:  The company has written policies pertaining to vacations, holidays, performance evaluations, and so forth.

Do not use a comma before an ampersand (&), which is often used to join the parts of a firm name.

          Davega, Moran & Lee is the leading architectural firm in this area.

Between Coordinate Adjectives (CA)         

When two or more adjectives separately modify the same noun, use a comma after each adjective except the last one unless all the adjectives are joined by conjunctions.

            This city has several long, narrow, dark streets.

            Yesterday was a bright, warm spring day.

            But:  We had a brief and interesting but unproductive meeting yesterday.

To determine whether adjectives are coordinate and should be separated by a comma, say them in a different order and insert and between them.  If the result makes sense, use a comma to separate the adjectives.

Our customers expect prompt, courteous service.  (Say: “Our customers expect courteous and prompt service.”  The result makes sense; therefore, the adjectives are coordinate and a comma should separate them.) 

We will have the picnic in the park if it is a bright, warm spring day.  (Note that a comma is not used after warm because spring is not one of the coordinate adjectives.  Saying “if it is a bright and warm and spring day” or “if it is a spring and bright and warm day” would not make sense; therefore, a comma is used only between bright and warm.) 

But:  We ate with short white plastic forks.  (Say: “We ate with plastic and short and white forks” and “we ate with white and short and plastic forks.”  Neither makes sense; therefore, the adjectives are not coordinate and no commas are used between them.)

After Introductory Words (INTRO)         

Use a comma after accordingly, consequently, yes, no, however, therefore, otherwise, or a similar word used to introduce a sentence or an independent clause within a sentence. 

No, I have not seen the report; however, I would like to obtain a copy of it. (Note that a semicolon, not a comma, is used between the independent clauses because they are not connected by and, but or some other coordinating conjunction.)

Therefore, we have decided to accept the other company’s bid

Be sure that the word is an introductory word, not a modifier, before you use a comma after it.  Also as illustrated below, no comma is necessary after the introductory word hence, thus, then, or still.

However, necessary repairs must be made. (However is an introductory word.)

However necessary the repairs may be, we cannot afford to make them now. (However functions as an adverb; it modifies the adjective necessary.)

Thus we should test several types of machines first; then we should select the one that best meets our needs.

After Introductory Phrases 

Always use a comma after an introductory infinitive or participial phrase at the beginning of a sentence or at the beginning of an independent clause within a clause.

To get there on time, we will need to leave at 8:30 a.m. (Infinitive  phrase.)

Lacking the necessary training, I was advised to take both of those courses. (Participial phrase.) 

I mailed the letter last week, but addressed incorrectly, it was returned today. (Note that a comma is used before and after the conjunction connecting the two independent clauses and after the introductory participial phrase.)

 Many writers use a comma after all introductory prepositional phrases.  However, a comma is not necessary after a short introductory prepositional phrase unless it contains a verb form, unless omitting the comma would cause misreading, or unless the phrase is a transitional expression or an absolute phrase.  An absolute phrase is one that has no grammatical relationship to the rest of the sentence..

At the end of its first year of operation, the company showed a small loss.

On June 15 you will receive the materials you requested. Or:  On June 15, you will receive the materials you requested.

In order to succeed, we must work harder and smarter. (The phrase contains the infinitive to succeed.)

By ordering now, we should save a few hundred dollars. (This short phrase contains the gerund ordering.)

If done properly, the corrections will not be noticeable. (The phrase is short, but it contains the participle done.)

In my opinion, everyone deserves a three-week vacation with pay. (In my opinion is an absolute phrase. It has no grammatical relationship to any part of the rest of the sentence.)

Construction is three months behind schedule; as a result, we will be unable to move into the new offices until the end of May. (This phrase functions as a transitional expression.)

In the spring, rain may cause flooding. (The  comma is necessary to prevent misreading. Not:  In spring rain may cause flooding.)

With Parenthetic Expressions  (PAR)

Use commas to set off a word, phrase, or clause that interrupts the main thought of a sentence and is not essential to the meaning or the grammatical completeness of a sentence. As illustrated below, such an expression sometimes qualifies or amends a statement, provides additional information, or contrasts with part of a statement. If the parenthetic expression occurs at the end of the sentence, do not use a comma after it.

We should, however, be able to meet the revised deadline.

Or: We should be able to meet the revised deadline, however.

Asking them to accept the proposal would, in my opinion, be a pointless exercise.

Hillary, or maybe it was someone else, suggested that the company install a local area network.

Lynn, not Ken, wrote the first draft of the report.

Bellwood Plaza, which is in the center of the city, attracts many tourists.

However, do not use commas to set off an element that is essential to the meaning or grammatical completeness of a sentence.

Nothing that we heard produced any change in our opinion. (Our opinion was not changed by anything that we heard.)

The company which offers the best service at the lowest price is Timmons Associates. (But: Timmons Associates, which offers the best service at the lowest price, is the company awarded the contract.)

With Appositives  (AP)

Use commas to set off a word or a group of words that is not essential to the meaning of a preceding noun or pronoun, such a word or group of words is a nonrestrictive appositive.  The appositive usually restates or gives more information about  the noun that precedes it in some way. 

            Dr. Pulaski, the principal speaker, is an industrial psychologist.

            Her first book, Principles of Effective Management, was published in 1984.

             He, Charles Houston, bought and renovated the building a few years ago.

If the word or group of  words is essential to the identification or meaning of the preceding noun or pronoun (a restrictive apposition), do not use commas to set it off.

The word overdo should not be confused with the word overdue. (If the words overdo and overdue were omitted, the sentence would not make sense. In each instance, the appositive is needed to make the meaning of word clear.)

Have you seen the movie Raiders of the Lost Ark?

We members of the committee should try to obtain ideas and suggestions from others. (Members of the committee is necessary to clarify the meaning of the pronoun we.)

With Names in Direct Address (DA)

Use commas to set off the name or title of a person being spoken to directly.

For further information, Mr. Lombardo, please contact our regional office in Duluth.

 

Vicky, do you have a copy of the company’s most recent annual report?

 

I very much appreciate your many helpful suggestions, Professor.

For Indicating Omissions  (OM)

Use a comma to indicate the omission of one or more words that can be easily understood from the context of the rest of the sentence.

             Carol is our general counsel; Bob, our business manager.

            The first conference was conducted by Paul; the most recent one, by Gina.

With Repeated Expressions (REP)

Use commas to separate words repeated for emphasis.

Their intentions are very, very clear to all of us.

You will have many, many opportunities to demonstrate your leadership ability.

With Direct Quotations  (DQ)

Use commas to set off a direst quotation from the rest of the sentence. A direct quotation is an exact repetition of spoken or written words. Note the placement of the commas in the following sentences.  Periods and commas ALWAYS go inside the quotation marks.  

“This strategy,” the firm’s spokesperson commented, “will enable us to compete effectively in both domestic and foreign markets.”

 

 The warranty states, “The original purchaser of this equipment may have other rights which vary state to state.”

"Our policy is to evaluate each employee’s job performance annually,” Ms. Kohlberg said.

With Titles, Degrees, and Seniority Terms

Use commas to set off titles and academic degrees following the names of persons. 

O. J. Wilford, director of human resources, is reviewing the company’s employment policies and procedures.

Esther Perez, Ph.D., is an expert on Latin American Affairs.

Unless you know that the owner of the name uses a comma before Jr., Sr., II, or a similar seniority term do not use commas to set off the term.

Eric Gustafson Jr. and Jack Moulton II are among the stockholders.

If the owner of the name uses a comma before the seniority term, use a comma after the term except when it occurs at the end of the sentence.

Mr. and Mrs. Earl M. Lawton, Sr., contributed to the scholarship fund.

One of the leaders of the local chapter is Allison McRae, III.

However, if a seniority term, academic degree, or similar designation is in the possessive form, do not use a comma after it.

James Donaldson, Sr.’s opinion is that the expense is fully deductible. (Note that the owner of the name does use a comma before the seniority term.)

Are you sure that this Darrell Jenkins IV’s current home address? (Note that the owner of the name does not use a comma before the seniority term.)

Have you read either of Samuel Petrie, Ed. D.’s historical novels?

With Inc. and Similar Terms  

Do not use a comma before or after Inc., Ltd., Limited, Incorporated, or a similar firm-name ending unless the official name of the organization (in the company's letterhead stationery) is written with a comma.  If a comma is used before the term, use a comma after it except at the end of a sentence.

As you will notice, McGraw-Hill, Inc., is the publisher of this book.

 

Does Time Inc. have its headquarters in Chicago?

 

Even if the official name is written with a comma before the term, do not use a comma after it when the term is in the possessive form.

Drake & Sons, Limited’s new manufacturing facilities will open in August.

 

Benton Associates Inc,’s annual report will be released this week.

In Dates

Within a sentence, use a comma before and after the year when it follows the month and day, do not use a comma before or after the year when it follows the month alone.

             Do you have a copy of the February 3, 1986, issue of Business Week magazine?

             The company was founded on June 10, 1955.

 But:  I think that the March 1985 sales figures should have been used in the comparison.

Also use a comma to separate a day of the week from the rest of a date, as illustrated in the sentence below.

She began working for our company on Monday, January 5, 1987, as a compensation specialist.

In Addresses

Within a sentence, use a comma after the name of the addressee (if included), the street name, the city name, and the state name unless it is followed by a ZIP+4 Code.  Use a comma after--but not before--a ZIP or Zip+4 code.

            Their stay in Niagara Falls, New York, was a very enjoyable one.

Please write to Ms. Audrey M. Greene, 2244 Lakeside Road, Rockford, Illinois 61102, as soon as possible.

In Numbers

Use a comma to separate thousands from hundreds, millions from hundred thousands, and so on, in numbers with five or more digits.  Unless it is necessary for consistency in style within a particular passage, a comma is not necessary in a number with four digits.

The company had 11,256 employees and gross sales of $91,356,200 at the end of last year.

 

The sponsors of the concert expect to sell at least 2500 tickets.

 

Of the 11,256 employees, approximately 2,200 are in overseas assignments. (Note the use of the comma in 2,200 for the sake of consistency in style.)

 

Do not use commas in numbers that represent years, page numbers, house numbers, ZIP Codes, telephone numbers, serial numbers, and decimal fractions.

By 1988            page 1142         5698 Pine Court Elmhurst, NY 11374

555-1212           5.6075              US55535788                  R42C930686

Between Consecutive Numbers

When two consecutive numbers are expressed in the same way (both in figures or both in words), use a comma to separate them.

            In 1986, 12,357 members and associate members participated in the survey.

            Of the four, two have been accepted.

With Weights, Measurements, Ages, and Similar Expressions 

Do not use commas to separate the parts of one weight, one capacity, one age, or a similar expression.

            The net weight is 2 pounds 5 ounces.

Their daughter is exactly 1 year 2 months 4 days old today.

When numbers are used with metric terms, use a space instead of a comma to separate thousands from hundreds, millions from hundred thousands, and so on.

12.320 km (kilometers) 68 100 m²  (square meters) 1 342 920 m³  (cubic meters)

©Division of Business, Economics & Mathematics, WVUP, 2011.  Updated 06/05/2012 .  Division Chair:  Steve.Morgan@mail.wvu.edu ;Business Division Office:  Lauriel.Edwards@mail.wvu.edu
Web Page Contact:  pam.braden@mail.wvu.edu West Virginia University at Parkersburg