How To Use Commas-7 Comma Rules

Last Updated on February 15, 2024.

Today, we’re going to talk about commas.


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Now, commas have three main functions: to separate clauses, to join dependent clauses, and to avoid confusion.

1. Choose the sentence that needs to have one or more commas added:
  1. Josh bought Annie flowers, chocolate, and a book.
  2. Josh bought Annie flowers chocolate and a book.

Question 1 of 2

2. Choose the version of the sentence that uses commas correctly:
  1. They began dating in December 2009. John was born on 31 May 2014.
  2. They began dating in December, 2009. John was born on 31 May, 2014.

Question 2 of 2


This lesson is provided by Onsego GED Prep.

Next lesson: End Punctuation
This lesson is a part of our GED Reasoning Through Language Arts Guide

Video Transcription

So, let’s take a look at the first use, to separate clauses. When dealing with punctuation, to know when, and when not, using commas in our writing is among the biggest problems students face.

Here are some specific rules to apply that are dictating when you should use commas.

Rule #1 – Use commas to separate various items in a series or list

Define a series or a list when there are three or more items. Every time we have a list of three items or more, we’re using commas to separate the items.

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For example:

  • I went over to the shop and bought trout, salmon, mackerel, and halibut.
  • In our American language class, we were reading Moby Dick, The Scarlet Letter, The Human Stain, and The House of Mirth.

Note, often, there is confusion about we should place a comma before the word “and”, so in front of the list’s last item.

Well. in general, we must place a comma in front of “and “ to separate the list’s last from the one proceeding it.

Without placing a comma here, readers might think that the list’s last two items are actually linked together there.

We use the basic rule that when in doubt, you should place a comma in front of “and “. Often, this rule is referred to as the “Oxford comma.”

Rule #2 – Use commas for the separation of multiple adjectives

If, in a sentence, more than one (1) adjective is used, separate these adjectives with a comma or by using “and “. We call this also “coordinate adjectives.”

For example:

  • He was an attractive, tall man.
  • Her white, glamorous, expensive car was stolen.

Rule #3 – Use commas for the separation of independent clauses that are linked with a coordinating conjunction

If we have two separate sentences that we want to make one, so creating a compound sentence, we use commas together with a coordinating conjunction (and, but, for, nor, yet, and so on) for linking them.

We should place the comma in front of our coordinating conjunction.

For example:

  • My English teacher was a good writer, and she taught me lots about grammar.
  • We left our house later than we had hoped, but we still were on time for the concert.

You may notice that our above sentences may be separated into two (2) different sentences. For example, the first sentence could also be written like:

  • My English Instructor was a good teacher. She taught me lots about grammar.

This is acceptable as well but if we would like to connect these smaller sentences into one (1) compound sentence, we need to add both coordinating conjunction and a comma to make our longer sentence grammatically correct.

Note that we cannot put a comma before the coordinating conjunction when we use it for linking phrases or words.

For example:

  • Correct is: I do like both math and English (no comma required). Incorrect is: I do like both math, and English (no comma needed).
  • Correct is: He acted hungrily but was not (no comma required). Incorrect is: He acted hungrily, but he was not (no comma needed).

Rule #4 – Use commas for setting off nonessential elements

Nonessential elements are words, phrases, or clauses that are not needed for the completion of sentences. In other words, if you would remove them, the sentences would still make sense and be grammatically correct. If by removing the elements, the meaning of these sentences would change, they are essential. A nonessential element must be offset with both a comma before and after the element.

Examples of nonessential elements:

  • We went to the movies with our neighbors, Sally and Ron, and later we had dinner.
  • Many students in the morning class, ENG 121, are fond of participating in discussions.
  • His best friend, Heather, is organizing a surprise party to celebrate his birthday.

Rule #5 – Use commas at the end of introductory elements

This sometimes is a confusing rule because it may be hard to identify these introductory elements.
Essentially, introductory elements begin a sentence by providing a sort of transition from background information or the last sentence before that independent clause.

An introductory element may come in the form of a prepositional phrase, a subordinate clause, or a transitional expression. When at the beginning of a sentence, one of these elements is used, we should place a comma after it.

For example:

  • After a prepositional phrase: In the hard-fought contest, our home team prevailed finally after two overtimes.
  • After a subordinate clause: Because you did well on your final essay, you should pass the class easily.
  • After a transitional expression: As an example, Aims is offering quite a few of services that may benefit students.

Note that commas may not always be needed after a short subordinate clause or prepositional phrase, as long as the reader will not get confused if you would leave it out. However, using commas after even short prepositional phrases or subordinate clauses is never wrong. So when in doubt, just use it.

Rule #6 – Use commas to introduce quotations

For example:

  • On the first student’s paper, the teacher wrote, “The thesis pretty well constructed but it should be placed at the end of the introduction.”
  • He told me, “I’m appreciating your willingness to participate in our classroom discussion.”

Rule #7 – Use commas with dates, addresses, and long numbers

When you use addresses in a sentence, regardless of whether they’re specific or not, commas should be put between streets and cities, between cities and states, and also at the end of an address.

For example:

  • Aims Community College (ACC) is found in Greeley, Colorado.
  • Please use this address, 5401 W 20th St, Greeley, CO 80634, for mail that you want to send to the college.

When you use specific dates in a sentence, commas should be placed between the days and the years and after the years as well.

For example:

  • August 24, 2016, is the day I started my very first semester of college.
  • The Declaration of Independence was signed on July 4, 1776, which led to the founding of the USA.

When we use long dates in our writing, we must place a comma at every thousandths place. Or, if we want to separate long numbers into groups of 3 (three), we start on the right.

For example:

  • The city of Denver is called “Mile High City” because it is situated some 5,280 ft. above sea level.
  • My new job will bring me a salary of some $40,000 per year.