Did you know the Chicago Manual of Style is what should be used as your punctuation and grammar guide when writing a book? Rules for article writing can be different and everyone knows you get a lot of creative leeway with blogs. Even so, the rules for using commas are consistent and make a big difference to the reader. Think of commas as little signals on how to read each sentence.
It’s as important to know when you shouldn’t use commas as it is to know how to use them properly. Below are some basic rules and some examples.
Use a comma to set off quotes.
In her book, she writes, “The way to discover this is tough.”
Use a comma before the attribution in a quote.
“I have always loved her,” he said.
In an attribution inside a quote, use a comma on each side of the quote.
“I wondered,” said Marie, “if you’d like to go on a hike.”
Don’t use a comma if you precede the quote with the word “that.”
She said that “her story is no different than that of anyone else.”
Don’t use a comma when setting a word apart with quotation marks.
She told us she was “sad” when she thought about him. (You don’t usually want to set a word off in quotation marks anyway, but at least you know not to use a comma!)
Separate the elements in a series (unless the items belong together, such as bread and butter)
She set the table, laying out forks, knives, and spoons in precise order.
She dished up her father’s plate, careful to separate the potatoes, green beans, and bread and butter.
Use a comma to connect two independent clauses
He ran as fast as he could, but it wasn’t fast enough to escape.
Note: sometimes one can do without the comma in a sentence that is brief, however it’s usually correct to have a comma before a conjunction (conjunctions are: and, but, yet, or, for, nor, and so).
Use a comma to set off introductory elements
Stopping to look at her own behavior, she suddenly realized how ridiculous she sounded.
Note: sometimes in brief introductory elements, one can forego the comma. If you are in doubt, do use the comma. If, when you read an introductory element, it sounds as if you need to pause, always use the comma.
Use a comma to set off parenthetical elements
A parenthetical element is a part of a sentence that can be removed without changing the essential meaning of that sentence. Appositives (words or phrases that refer to the same person) are almost always treated as parenthetical elements.
Her desire, despite what he said, was to finish the project.
Helene, her mother and best friend, would soon start her journey.
Note: Sometimes the appositive and the word it identifies are closely related and the comma can be omitted.
Example: Her son Kevin is headed to Paris.
When the name of a city and that city’s state or country are mentioned together, the state or country need commas around them
She grew up in Ontario, Oregon, in the United States.
When the state becomes possessive, this rule no longer applies
Ontario, Oregon’s claim to fame is that it’s in the heart of what’s known as Treasure Valley.
Use commas with an adverbial clause (an adverbial clause refers to or functions as an adverb) that begins a sentence
Because Trevor had become accustomed to the training wheels, he rode his bicycle confidently down the sidewalk.
Note: When an adverbial clause comes later in the sentence, a writer needs to determine if the meaning is clear without the comma.
Example: Trevor rode his bicycle down the sidewalk because he’d become confident due to using training wheels.
Here’s an example where the sentence would be unclear without the comma:
I knew the space shuttle would launch because my uncle worked with the media. (Without the comma, it seems the space shuttle launch would be due to the uncle working with the media.)
I knew the space shuttle would launch, because my uncle worked with the media. (With the use of a comma, this person knows the space shuttle will launch because they’ve heard so from the uncle.)
Never put a comma between a subject and its verb
Challenging another to a duel (subject) is (verb) hardly necessary.
An absolute phrase is always treated as a parenthetical element, as is an interjection
Their hunger forgotten, the children ran to meet their parents.
Absolutely, you must not forget, that without preparation your journey will be a challenge.
When a person is being spoken to, use commas on each side of the name
Think about it, Kevin, and you’ll see what I mean.
The reverse needs no commas: You’ll see what I mean if you think about it Kevin.
Use commas to separate adjectives unless the adjectives belong together
He viewed himself as a smart, well-groomed, and charming man.
She didn’t particularly like being considered a little old lady.
Use commas to set off phrases that express contrast
He describes his boss as being thoughtless, not unkind.
The color was vivid, though not as bright as she’d described.
Use a comma after a title
Barak Obama, President of the United States, spoke about reform.
When a date is included between the month and the year, include a comma, otherwise do not use a comma
July 4, 1776, is perhaps the most significant date in American history.
July 1776 was one of the most important months in American history.
Use a comma to keep from confusing your reader
Outside the rooster crowed and strutted. (You can see how this confuses the poor reader, who is left to wonder how the outside of the rooster is doing the crowing and strutting.)
Correct use of a comma: Outside, the rooster crowed and strutted.
Start a review of your manuscript by reading out loud to see where natural pauses fall, then check to see if one of the rules I’ve listed here apply. Sit down and write first, as you don’t want the magic of your writing to get bogged down in the details. Spend your editing and rewriting time during those periods of time when you’re not charged up with excitement about your story. Review the rules whenever you’re in doubt and soon you’ll have them mastered.