Danielle McLeod is a highly qualified secondary English Language Arts Instructor who brings a diverse educational background to her classroom. With degrees in science, English, and literacy, she has worked to create cross-curricular materials to bridge learning gaps and help students focus on effective writing and speech techniques. Currently working as a dual credit technical writing instructor at a Career and Technical Education Center, her curriculum development surrounds student focus on effective communication for future career choices.
The comma is used more than any other punctuation in writing. Because of this, there are many misinterpretations of where a comma belongs, rule misuses, and myths provided by poor teaching practices.
No, you do not use a comma anytime you take a breath when reading a sentence, but a comma does designate a pause. Take a look at how you should use commas to help separate essential elements and make your writing clear and concise.
A comma [,] tells a reader to take a short pause before continuing with reading. It separates basic elements and is used to set off added details and features within a sentence. Without commas, sentences would jumble words together and create confusion surrounding the importance of specific information.
A compound sentence is when two or more independent clauses are joined by a coordinating conjunction such as and, but, for, or, nor, so, or yet. A comma is needed to separate the independent clauses and is an essential punctuation mark when used.
Examples of When NOT to Use a Comma With a Conjunction
Do not make the error of automatically inserting a comma when you see a conjunction. Coordinating conjunctions also join compound subjects, verbs, prepositional phrases, and clauses. Not all require the use of a comma.
| Compound Subject | The students and the parents met with the teachers last night. |
| Compound Verb | We love to swim and hike when on vacation. |
| To Prepositional Phrases | I threw the baseball to the catcher and to the second baseman. |
| Two Subordinate Clauses | My children love to read books only if the material is exciting and only if the pages have pictures. |
Use commas to separate three or more words, prepositional phrases, or clauses within a sentence. This use is called a serial comma or Oxford comma and helps avoid confusion when more than one thing is used in a list. See further examples of that here: How to Use Oxford Commas.
| Words | I read through all my handouts, the textbook, and classroom notes when preparing for the exam. |
| Prepositional Phrases | Scotland has been shaped by its geography, by its people, and by its heritage. |
| Clauses | There is proof that the Americas were settled by tribes that traveled across the Bearing Straits, the Vikings who came by boat, and later by Europeans searching for a passage to India. |
It is permissible to omit the last comma in a series as long as this pattern is followed throughout the material and does not create confusion.
Examples of When NOT to Use a Comma In a Series
Commas are not needed if conjunctions separate all the items in a series.
Commas are not needed to separate pairs of items listed together within a sentence.
Commas divide adjectives of equal rank. These are called coordinator adjectives and are defined using two simple rules:
Cumulative adjectives must stay in the order they are given to avoid confusing the sentence. You do not use commas between adjectives that must remain in a specific order.
Commas are used after introductory words, phrases, or clauses. This usage allows readers to recognize that the initial information has come to a close and that the main part of the sentence will follow. Look at the following examples to help you:
Introductory Words
Nouns of Direct Address
Common Expressions/Interjections
Introductory Adverbs
Prepositional Phrases
Participial Phrases
Infinitive Phrases
Adverb Clauses
A parenthetical expression is a word or phrase that interrupts the flow of a sentence. Commas help offset the expression to provide clarity.
| Expressions | Examples | In a Sentence |
| Nouns of Direct Address | Tim, Mr. Clements, my son, sweetheart | We will leave, Micheal, as soon as the train arrives. |
| Conjunctive Adverbs | besides, also, however, furthermore, indeed, moreover, instead, otherwise, nevertheless, thus, therefore | The dogs, however, refused to get out of the muddy puddle, and all received a bath later that night. |
| Common Expressions/Interjections | in my opinion, of course, on the other hand, by the way, I feel, in the first place | Her garden, by the way, is full of heritage blooms she has cultured from seeds. |
| Contrasting Expressions | Not mine, not there, not that one | It was hers, not mine, which is why you were confused in the first place. |
Nonessential expressions are added information that is not needed for a reader to understand the meaning of a sentence. It provides additional detail but will not change the sentence meaning if removed. Commas are required to help offset the expression since it interrupts the flow of a sentence.
It is important to recognize the difference between an essential and nonessential expression. Commas are not used with essential expressions because they provide necessary information in a sentence. Removing essential expressions from a sentence changes the meaning.
| Essential Expression Examples | Nonessential Expression Examples |
| The child holding the teddy bear is boarding the plane. | Jonathon Ayers, holding the teddy bear, is boarding the plane. |
| The famous actor Michael Smith has won many awards. | Michael Smith, a famous actor, has won many awards. |
Commas are used in everyday writing scenarios concerning technical communication and correspondence, formatting materials, and even addresses. The following examples help provide you with their proper use in various situations to ensure there is no confusion.
When citing a specific place or geographical location made up of two or more places, a comma is necessary to separate each item.
When a date includes two or more parts, use a comma after each item. An exception to this rule is when you use a month followed by a day or a year.
When a name is followed by one or more commas, use a comma after the name and after each title.
An address that consists of two or more parts requires commas to separate each part. Avoid using commas if prepositions join the parts of an address.
Commas follow all salutations and closings in a letter.
| Salutations | Dear Mr. Smith, Dear Aunt Sarah, Dear Mr. and Mrs. Jonathon Swift, Dear Monica, |
| Closings | Sincerely, Yours Truly, Respectively, In Appreciation, Regards, |
Numbers that have more than three digits require the use of a comma after every third digit from the right to designate place.
There are some exceptions to this rule. Do not use a comma with the following:
| Zip Code | 48009 |
| Telephone Numbers | (716) 555-2020 |
| Page Numbers | Page 4306 |
| House Numbers | 19257 North Lamson |
| Serial/Tracking/Social Security Numbers | 154 05 3007 24576 |
Words and phrases may be purposely omitted from a sentence to create an elliptical sentence. An elliptical sentence structure implies omitted words by using other elements within the sentence. To provide clarity, insert a comma where words have been left out as a visual clue that an omission exists.
Commas are used to set off direct quotations from the rest of the sentence.
Understanding the proper use of commas can help you avoid making careless mistakes that may change the meaning of your sentences. Overuse of commas is common, as is poor placement. Even though they might not create problems overall with your message, you want your writing to sound sophisticated and polished to your readers.
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