Hundreds of years ago, British playwright William Shakespeare came down from Mount Everest with two huge, stone tablets engraved with the ten basic rules about commas. Okay, that’s not even close to being true, but just as Moses had his ten commandments to live by, writers have ten basic comma rules that they need to know if they want their writing to be clear and precise.
One. Commas are used to separate the parts of complete dates and addresses. This is probably the easiest rule of all because most people know that they need to separate the date from the year and the city from the state when they write about their birthdays or their homes. (“I was born on February 29, 1960. I grew up in Amsterdam, New York.”)
Two. Commas are used to separate items in a list of three or more. If you have only two items — like “peanut butter and jelly” — you don’t need a comma, but once you add a third item, you need commas. (“Please go to the store and buy peanut butter, jelly, and bread.”) The comma before the word “and” is called the “serial comma” (for items in a series), and some people feel this comma is not necessary because the word “and” separates the second and third items. However, without that serial comma, a misreading of your sentence might occur, so most instructors will insist on that comma before the word “and.”
Three. Commas are used to separate the introductory part of a sentence from the main idea of the sentence. If you introduce your main idea with a short phrase, you should insert a comma after that phrase to tell the reader to pause before the main idea. (“After class, I will eat lunch.”) A minor controversy exists regarding this rule as well. Some people feel the comma is not necessary after a short introductory phrase because the reader doesn’t really need to pause after two words in a six-word sentence. Again, however, to avoid a possible misreading of the sentence, and also for the sake of consistency, your instructors will generally expect you to insert a comma after your introductory phrase, no matter how long or short it may be.
Four. Commas are used after a dependent phrase (one that can’t stand on its own) at the beginning of a sentence but not if the dependent phrase occurs at the end of the sentence. The first half of this rule is obviously similar to the previous rule. (“If it rains, the game will be canceled.”) The phrase “If it rains” is dependent because it does not express a complete thought, so you need to use a comma to separate that phrase from the main idea: “the game will be canceled.” However, if you start with the main idea and end with the dependent phrase, you do not need the comma separating them. (“The game will be canceled if it rains.”)
Five. Commas are also used to show contrast, especially when you add a contradictory thought to your main idea by using the words “not, never, or unlike.” Here are three examples: (1) “I like the Mets, not the Yankees.” (2) “He is so cool, never anxious at all.” (3) “Young children can be brutally honest, unlike most adults.”
Six. Commas are used to separate two independent thoughts which are connected by one of the seven coordinating conjunctions: “for, and, nor, but, or, yet, so.” Thus, you may want to remember the acronym “FANBOYS” to remember these coordinating conjunctions. (“I am tired, but I can’t fall asleep.”) However, once some students grasp the idea of connecting two independent thoughts, these students often put a comma before the word “because.” (“I can’t sleep, because I’ve had too much coffee.”) In this example, though, the comma is unnecessary because the word “because” is not one of the FANBOYS. While exceptions to the general rule may exist, typically, you don’t need a comma before the word “because.”
Seven. Commas are used to introduce quotations, essentially to separate a direct quote from the rest of the sentence. (President John F. Kennedy said, “Ask not what your country can do for you — ask what you can do for your country.”) The comma usually precedes the quoted words in most essays, but it often follows the quotation when a writer is using dialogue. (“I can’t trust you,” Pamela said to her boyfriend.)
Eight. Commas are used whenever you speak directly to someone, in your writing. (“Bill, may I borrow your car tonight?”) This is called “direct address.” Usually, the comma will follow the person’s name, but the comma could precede the person’s name if the name is used at the end of the sentence. (“Can you give me a ride, Bill?”) Also, you would need two commas if the person’s name is in the middle of the sentence. (“Please, Bill, give me a ride.”)
Nine. Commas are used whenever you include “extra” information in your sentence. Extra information typically includes details that are not essential but helpful. For example, if you wrote “Tina complimented me at work today,” that sentence is not quite as strong or as informative as “Tina, my boss, complimented me at work today.” Other types of extra information include transitional words or phrases that make your writing easier to follow. (“First, Mr. Smith should be elected because he has budgetary experience, and, second, because he is, as you may be aware, committed to reducing the national deficit.”)
Ten. Commas are used when you have more than one adjective to describe a noun. (“He drives a sleek, red Mustang.”) These adjectives are called “coordinate” adjectives because they are working together to describe the Mustang; the Mustang is sleek and red. If your adjectives build on one another, however (“cumulative adjectives”), you do not need commas. (“He drives a bright red Mustang.”) In the second example, the word “bright” describes “red” and red describes the Mustang.
Typically, struggling writers use either too many commas or too few, and as a result, their sentences are often choppy or hard to follow. Now that you know the ten commandments of commas, however, you can write more clearly and more confidently. Who knows? You may become the next William Shakespeare.