Certified Data Entry Operator Learning Resources Punctuation Rules

Learning Resources

Punctuation Rules

Some general punctuation rules to follow are:


  • Use a period at the end of a sentence. Example: I enjoyed the movie.
  • Use a period after an initial. Example: M. E. Kerr is a wonderful author.
  • Use a period after an abbreviation. Example: We welcomed Mrs. Simmons to our team.
  • Use a period as a decimal point. Example: The workers received a 2.1 percent raise.
  • Use a period to separate dollars and cents. Example: The book cost $4.95.
  • Use a period after each number in a list printed vertically. Example:  For the example, look at the lists on this page.


  • Use an exclamation point at the end of sentence, phrase, or word to indicate strong emotion. (Never use more than one exclamation point.) Example: Wow! I never thought Mom would let us go to the concert!
  • Unacceptable: Wow!! I never thought Mom would let us go to the concert!!!!!!


  • Use a question mark at the end of a question. Example: Did Steven go with you?
  • Use a question mark at the end of a declarative statement that you want to emphasize as not believing the statement.
  • She's our new teacher?
  • Use a question mark with parentheses to indicate that you are not sure of a spelling or other fact.
  • I have to visit an orthopeadic (?) doctor next week.


  • Use a comma after each item in a series of at least three items. (It has become acceptable to omit the comma before the conjunction in a series. However, it is important to remain consistent.) Example: I still need to take a test, write an essay, and check out a book. Example: I dislike spinach, broccoli, and cauliflower.
  • Acceptable: I dislike spinach, broccoli and cauliflower.
  • Use commas after the street address and city in an address. (Do not use a comma after the state.) Example: The address is 1234 Apple Street, Midtown, Kansas 98765.
  • Use a comma after the day and the year in a date. (No commas are used in dates when using the MLA style.) Example: Connie's birthday is February 20, 1965.
  • MLA version: Connie's birthday is 20 February 1965.
  • Use a comma to clarify large numbers. Counting from right to left, a comma is needed after every 3 digits. This rule does not apply to years, where no commas are used at all. Example: In 1998 the population of Claremont was 23,899.
  • Use a comma to set off an interruption in the main thought of a sentence. Example: Rosa, of course, will bring her folding chairs.
  • Use a comma to separate two or more adjectives that equally modify the same noun. (If you aren't sure whether to use a comma to separate the adjectives or not, say the sentence with the word and in place of the comma.  If it makes sense, then use the comma.) Example: Jill was having problems with the unruly, disruptive children.
  • Use a comma after a dependent clause that begins a sentence. (Never use a comma before a dependent clause at the end of a sentence.) Example: If Mr. Wilson complains, we'll invite him for a snack. Example: We'll invite Mr. Wilson for a snack if he complains.
  • Use a comma before the conjunction in a compound sentence.  However, if the two independent clauses are very short, you do not need the comma. Example: We had a lot of fun, so I'll have another party soon. Example: She spoke and I took notes.
  • When quoting, put a comma to the left of a quotation mark that does not already have a period, question mark, or exclamation point. (It is much easier to remember this rule than to worry about "inside" and "outside".) Example: Ariel said, "I knew you would win the contest."
  • Use a comma after a mild interjection, such as oh or well. Example: Oh, the test was not that difficult.
  • Use a comma after a noun of direct address. Example: Kodi, didn't I ask you to clean your room?
  • Use a comma after the greeting in a personal letter. Example:  Dear Aunt Sheila,
  • Use a comma after the closing of a letter. Example: Sincerely,
  • Use a comma to indicate where a pause is necessary in order to avoid confusion.  (Sometimes rewriting the sentence is a better choice.) Example: After Kelly, Jennifer gets a turn. Example: Maria came in, in quite a hurry.
  • Use a comma after an appositive. (An appositive is a noun or noun phrase that gives additional information about the noun that it follows.  Do not use a comma after a restrictive appositive, which is one that cannot be removed from the sentence without changing the meaning of the sentence.) Example: Wesley, my brother, is an optician.
  • Use a comma to set off the abbreviation etc. Example: I went to the store to get napkins, plates, cups, forks, etc.


  • Use a semicolon to join two independent clauses. (This eliminates the need for a comma and a conjunction.) Example: Casey read a book; then he did a book report.
  • Use a semicolon to separate items in a series when those items contain punctuation such as a comma. Example: We went on field trips to Topeka, Kansas; Freedom, Oklahoma; and Amarillo, Texas.


  • Use a colon between numerals indicating hours and minutes. Example: School starts at 8:05 a.m.
  • Use a colon to introduce a list that appears after an independent clause.  (Introductory words such as following go somewhere before the colon to help introduce the list.) Example: You need the following items for class: pencil, pens, paper, ruler, and glue.
  • When mentioning a volume number and page number, use a colon between the two items. Example: You will find information about Mexico in Grolier Encyclopedia 17:245.
  • Use a colon after the greeting of a business letter. Example: Dear Sir:
  • Use a colon between the title and subtitle of a book. Example: Reading Strategies That Work: Teaching Your Students to Become Better Readers is an excellent resource.
  • Use a colon between the chapter and verse numbers for parts of the Bible.
  •  Example:  Please read Genesis 1:3.   


  • Use an apostrophe in a contraction to show where letters have been omitted, or left out. Example: I don't think I can do this. (The apostrophe shows that the letter
  • Use an apostrophe when you leave out the first two numbers of a year.
  • She was in the class of '93.
  • For a singular noun that does not end in -s, add 's. Example: The lady's hands were trembling.
  • For a one syllable singular noun that ends in possessive. Example: It is my boss's birthday today.
  • If a singular noun has more than one syllable and ends in -s it is acceptable to use 's OR to use only an apostrophe after the -s. (It is important to remain consistent.) Example: The metropolis's citizens were very friendly during our visit.
  • Acceptable: The metropolis' citizens were very friendly during our visit.
  • To form the possessive of a singular proper noun ending in -s, it is acceptable to add 's OR to add only an apostrophe. (It is important to remain consistent.) Example: Mr. Ness's classroom is very inviting.
  • Acceptable: Mr. Ness' classroom is very inviting.
  • If a plural noun ends in -s, add an apostrophe after the -s. Example: The ladies' restroom was a mess.
  • If a plural noun does not end with an -s, form the possessive by using an apostrophe before an -s. Example: The mice's tails were caught in a trap.
  • For a compound noun, place the possessive ending after the last word. Example: My mother-in-law's car was in the garage during the hail storm. (singular) Example: My brothers-in-law's cars were damaged in the hail storm. (plural)
  • To show possession of the same object by more than one noun, only make the last noun in the series possessive. Example: I'm looking for Mrs. Garcia, Mrs. Lee, and Miss Carter's office. (They all share the same office.) Example: I'm looking for Mrs. Garcia's, Mrs. Lee's, and Miss Carter's offices. (Each person has her own office.)
  • Use an apostrophe to form the plural of a number, letter, sign, or word used as a word. Example: Check to see that you used the +'s and -'s correctly.


  • Use quotation marks before and after a direct quote.  If the speaker tag interrupts the quoted material, then two sets of quotation marks are needed. However, do not put quotation marks around the speaker tag. Example: "I think my leg is broken," Jesse whimpered. Example: Did Mrs. Steele just say, "We are going to have a test today"? Example: "I can't move." Maria whispered, "I'm too scared."
  • Put quotation marks around the titles of short works, such as articles, songs, short stories, or poems. Example: Have you heard the song "Love Me Tender," by Elvis Presley?
  • Place quotation marks around words, letters, or symbols that are slang or being discussed or used in a special way. (Underlining can be used for the same purpose.) Example: I have a hard time spelling "miscellaneous." Example:  I have a hard time spelling miscellaneous.
  • Use single quotation marks for quotation marks within quotations.

  Example: "Have your read the poem, 'The Raven,' by Edgar Alan Poe?" I asked Chris.

  • Any punctuation used goes to the left of a quotation mark.  However, if the punctuation is used to punctuate the whole sentence and not just what is inside the quotation marks, then it goes to the right.

  Example:  Have you read the poem, "Anabel Lee"?


  • Use an ellipsis to indicate a pause. Example: You mean ... I ... uh ... we have a test today?
  • Use an ellipsis to indicate omitted words in a quotation. Example: "Then you'd blast off ... on screen, as if you were looking out ... of a spaceship."
  • If the ellipses comes at the end of your sentence, you still need end punctuation, even it is a period.
  • I listened carefully as the teacher read Lincoln's inaugural address.  "Four score and seven years ago ...."


  • Use a hyphen in compound numbers from twenty-one to ninety-nine. Example: The final score was seventy-eight to sixty-two.
  • Use a hyphen between the numbers in a fraction. Example: I only used three-fourths of the flour you gave me.
  • Use a hyphen to form some compound words, especially compound adjectives that appear for the nouns they modify. Example: The court took a ten-minute recess.
  • Use a hyphen to join a capital letter to a word. Example: I had to have my arm X-rayed.
  • Use a hyphen to show a family relationship, except "grand" and "half." Example:  My sister-in-law helps take care of my great-aunt. Example:  We are going to go visit my grandparents while we are in town. Example:  Connie just found out that she has a half sister.


  • Use a pair of dashes to indicate a sudden interruption in a sentence. (One handwritten dash is twice as long as a hyphen. One typewritten dash is one hyphen followed by another.) Example: There is one thing--actually several things--that I need to tell you.
  • Use a dash to attach an afterthought to an already complete sentence. Example: Sarah bought a new pet yesterday--a boa constrictor.
  • Use a dash after a series of introductory elements. Example: Murder, armed robbery, assault--he has a long list of felonies on his record.


  • Use a set of parentheses around a word or phrase in a sentence that adds information or makes an idea more clear. (Punctuation is placed inside the parentheses to mark the material in the parentheses. Punctuation is placed outside the parentheses to mark the entire sentence. When the material in parentheses is longer than one sentence [such as this information], then the punctuation for the final sentence is placed inside the parentheses.)   Example: Your essay (all nine pages of it) is on my desk.
  • Do not use parentheses within parentheses.  Use brackets in place of the inner parentheses. Example:  Please refer to Julius Caesar (Act IV, scene i [page 72]).


  • Use brackets around around words of your own that you add to the words of someone you are quoting. Example: The news anchor announced, "It is my sad duty to inform our audience that we are now at war [with Iraq]."


  • It is more acceptable to use italics when available.
  • Underline titles of long works such as books, magazines, albums, movies, etc. (Do not underline end punctuation.)  Example: We use The Language Handbook to study grammar. Example: We use The Language Handbook to study grammar.
  • Underline foreign words which are not commonly used in everyday English. Example: If you look closely, you'll see e pluribus on most U.S. currency. Example: If you look closely, you'll see e pluribus on most U.S. currency.
  • Underline a word, number, or letter which is being discussed or used in a special way. (Quotation marks can be used for the same purpose.) Example: Remember to dot every i and cross every t. Example: Remember to dot every i and cross every t.
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