Guide to Using Punctuation

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Guide to using punctuation

One thing I’ve noticed quite often is that there is quite a bit of confusion about when and how to use certain types of punctuation. The following clears up how and when to use commas, periods, semicolons, and colons, along with a few others.


To figure out if you need to use a comma, period, or semicolon, first consider the purpose of the punctuation. For example:

  • When I drove to the store yesterday_ my car broke down.

The purpose of the punctuation in this sentence is to link the first part of the sentence (dependent clause) with the second part (independent clause), so you would use a comma.

  • When I drove to the store yesterday, my car broke down.

You can’t use a period or semicolon because, “When I drove to the store yesterday,” is not a complete thought.


You use a period to finish a thought. For example:

  • I drove to the store yesterday_ My car broke down_

You would use a period after both sentences because they are two distinct thoughts.

  • I drove to the store yesterday. My car broke down.


You can also use a semicolon in the example above because the expressed are related to one another.

  • I drove to the store yesterday; my car broke down.

For more about the correct use of semicolons, check out my blog post from a couple months ago.


In my experience, a lot of people seem to confuse semicolons and colons. You use colons most commonly to introduce a list, but you can also use them (in some cases!) to join two sentences.

  • My grocery list:
    • Apples
    • Oranges
    • Bread

People often use colons unnecessarily, such as when they introduce a list that does not need a colon.

  • Incorrect: I went to the store and bought: apples, oranges, and bread.
  • Correct: I went to the store and bought apples, oranges, and bread.

While the semicolon joins two ideas together into one sentence, the colon expands on the idea introduced in the first independent clause.

  • He waited three weeks but she finally gave him an answer: she would marry him when they graduated.

Hyphens and En and Em dashes

There are three different punctuation marks that people commonly refer to as dashes, but they all perform different functions.

Hyphens (the shortest of the three) connect two things to create a single concept or to modify a noun.

  • Third-degree burn
  • Nineteen-year-old college student

According to the Chicago Manual of Style, en-dashes “specify any kind of range” and “connect a prefix to a proper open compound.”

  • Read pages 10–40.
  • Post–9/11 security measures

The em-dash (which is slightly longer than the en-dash) allows the writer to add a thought into a sentence.

  • When I went to the store and my car broke down — the engine had overheated — I had to walk a mile to get home.

For more information, visit The Writing Center at University of North Carolina Chapel Hill’s page on semicolons, colons, and dashes.

Exclamation Points

I’ve always said that you should use exclamation points sparingly when writing. If you want to convey that what you are writing is important, your writing itself should do that, not the punctuation at the end.

That is not to say that you can never use exclamation points, but use them cautiously. I agree with Grammarly’s sentiment on exclamation points that if you already used one, it’s probable that you don’t need another one.


Another overused punctuation mark is the ellipsis. To correctly use an ellipsis in more formal writing, you should only use them to indicate that text is missing from a quote.

  • We the People of the United Statesdo ordain and establish this Constitution for the United States of America.

In informal writing, writers often use ellipses to indicate a pause in thought, hesitation, or a thought trailing off.

  • I just thought that we might go . . . well, actually I might just stay home.
  • So, should I just go . . . ?

I’ve also covered the proper way to use quotation marks and apostrophes in prior posts. Feel free to check those out for any questions you might have.

For any questions you have about subject-verb agreement, check out last week’s post and come back next week for a summary of all the grammar controversies I’ve covered so far.

And as always, if you need help with content writing, give us a call at 888-521-3880.