Demystifying the Comma, part 1

by Laura Brown 

Originally Published Aug 21, 2013 

In this week’s post, we look at the comma–the most frequently used punctuation mark and one that causes more than its fair share of confusion. Most people have at least some uncertainty about when to use a comma, and most people punctuate by the seat of their pants–whenever it “feels right.” Luckily there are clear rules about when to use a comma, so you don’t have to guess every time. Learn these few rules, and you’ll never wonder if you’re doing it right again. Let’s start by looking at the most common uses.

Use a comma:

When joining two full sentences with and, or, but, nor, or for.
– Jennifer worked for the agency, but I never knew her there.
– The CFO liked Marco’s resume, and I think we should interview him.

Between items in a series.
– They are looking for people in marketing, sales, and account management.
– The caterer offers vegetarian, gluten-free, and kosher selections.
(The comma before the “and” is optional. It’s known as a “serial comma” or “Oxford comma,” and we’ll talk more about it in a later post.)

After a long introductory phrase or clause.
– With the presentation behind him, Paul was able to enjoy the rest of the trip.
– Because of the shortage of housing in the city, they moved to the suburbs.
(It’s up to you to decide if your introductory phrase or clause is long enough to justify using a comma. If you think there’s any risk of confusion, you’re better off inserting a comma.)
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Those are the basics! In Part 2 of “Demystifying the Comma,” we’ll look at a few more rules for comma usage. Don’t expect yourself to memorize these rules right off the bat: the best way to remember grammar and punctuation rules is through using them. Bookmark these posts and refer to them whenever you have a comma-related question.
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