Common Punctuation Conventions

Whether you are a novice writer or a seasoned professional, you should always proofread your work carefully before sharing or publishing it. Punctuation mistakes can give a wrong first impression of you and what you’re attempting to project about your writing skills.

There are no fixed rules of proper punctuation, but there are conventions that we are expected to follow. The majority of these conventions relate to punctuation marks and how to use them. Let’s look at some of the most common punctuation marks.

Using End-of-Sentence Punctuation Marks

  1. Period
    Every sentence has at least one punctuation mark – the one at the end. The period is the most common. It is used to end sentences that are declarative. A declarative sentence is a sentence in the form of a statement rather than a question, command, or exclamation. Most sentences are declarative.
  1. Question Mark
    The question mark is used to end a sentence. It is used to end an interrogative sentence – essentially, any sentence that asks a question.
  1. Exclamation Mark
    The exclamation mark is used to end commands or exclamatory sentences.It suggests excitement or strong emphasis. The exclamation mark is also used to end exclamations — short expressions of intense emotion that are often only one word long.

Using Commas

The comma separates the structural elements of sentences into manageable segments. The comma gives the reader or speaker a break, and it can help emphasize a point. The Purdue OWL has a Quick Guide to Commas that will assist in your understanding of when to use commas. Basically,

  • Use commas to separate independent clauses in a sentence.
  • Use commas after introductory words, phrases, or clauses that come before the main clause.
  • Use a pair of commas to separate an aside from the main body of the sentence.
  • Do not use commas to separate essential elements of the sentence.
  • Use commas to separate three or more words, phrases, or clauses written in a series.
  • Use commas to set off all geographical names, items in dates (except the month and day), addresses (except the street number and name), and titles in names.
  • Use a comma to shift between the main discourse and a quotation.
    Right: She asked in a loud voice, “Is anybody home?”
    Wrong: She asked in a loud voice “Is anybody home?”
  • Use commas if they prevent confusion.

The Oxford Comma

The Oxford comma (also serial comma or Harvard comma) comes into play when separating three or more words, phrases, or clauses written in a series. When using the Oxford comma, all items are separated by a comma. Many people prefer not to use this style and will omit the final comma. For example,

With an Oxford Comma: I like apples, oranges, plums, and strawberries.
Without an Oxford Comma: I like apples, oranges, plums and strawberries.

Using Quotation Marks

Quotation marks are used to quote another person’s words exactly, whether they are spoken or written. Quotation marks also set off the titles of things that do not usually stand by themselves: short stories, poems, and articles. Quotation marks can also be used to denote irony or sarcasm, or to note something unusual about it. Single quotation marks are used to indicate a quotation within a quotation. Remember that quotation marks always come in pairs. Do not open a quotation and forget to close it at the end of the quoted material.

Punctuation with quotations

Punctuation belonging to the original quote should be inside the quote marks. Punctuation relating to the entire sentence should be outside. Always put colons and semicolons outside quotes. Put commas and periods inside quotations unless followed by parenthesis.

Using Colons, Semicolons, and Parentheses

  1. Colon
    Colons should be used after a complete statement in order to introduce one or more directly related ideas, such as a series of directions, a list, or a quotation or other comment illustrating or explaining the statement. Colons are also used to introduce a new concept or example and to separate parts of a title.
    Right: We wanted to have a three-course meal: lamb chops, pureed potatoes and a salmon mousse.
    Wrong: We wanted to have a three-course meal, lamb chops, pureed potatoes and a salmon mousse.
  1. Semicolon
    Semicolons are used to separate two related but independent clauses. They are also used to separate a complex series of items or if the elements of the list already include commas.
    Right: On Monday, when everyone was tired after the weekend, students kept silent; however, on Wednesday, the situation changed.
    Wrong: On Monday, when everyone was tired after the weekend, students kept silent, however, on Wednesday, the situation changed. (Using too many commas can be rather confusing.)
  1. Parentheses
    Parentheses are used to clarify, to convey an afterthought, or for personal comments.

Using Apostrophes

Apostrophes perform two basic functions: (1) to form possessives of nouns and (2) to form contractions that indicate one or more missing letters. The apostrophe should not be used to indicate a plural. See or for more extensive discussions of the apostrophe.

(1) The general rule is that the possessive of a singular noun is formed by adding an apostrophe and s, whether the singular noun ends in s or not. (This position can be controversial.)

  • the lawyer’s fee
  • the child’s toy
  • Jones’s house
  • anyone’s guess
  • a week’s vacation

The possessive of a plural noun is formed by adding only an apostrophe when the noun ends in s, and by adding both an apostrophe and s when it ends in a letter other than s.

  • children’s toys
  • the twins’ parents
  • the student teachers’ supervisor
  • the boys’ baseball team
  • the alumni’s fundraising

(2) Sometimes, especially in informal writing, apostrophes are used to indicate one or more missing letters. For example, the word “don’t” is short for “do not”; other examples include isn’t, wouldn’t, and can’t.

Other Punctuation Marks

Other punctuation marks include brackets, ellipses, dashes, hyphens, and slashes. Brackets are used to set apart or insert text within other text. Ellipses are used to indicate the intentional leaving out of a word, to trail off at the end of a sentence, to pause, or to show an unfinished thought. Dashes create a range or set off words, phrases, sentences for special emphasis. Hyphens join words or syllables. The slash is used to indicate a choice between the words it separates.

We could discuss punctuation for days. The point is to be aware and check your work before publishing it.