Do You Need a Comma Before But, Because, Which or And?

Instructor: Shelly Merrell

Shelly has a Master's of Education. Most recent professional experience is an educational diagnostician. Prior, she taught for 8 years.

In this lesson, you will learn the rules for using a comma before 'but,' 'and,' 'because,' 'which,' and 'or.' You will practice with some examples of when to apply the rules to gain a better understanding. Lastly, you will have practice mastering these grammar skills.

Punctuation Marks

There are different punctuation marks in the English language. Our language uses exclamation marks, semicolons, dashes, and commas - just to name a few. Each mark has it's own job to do. Let's read on to learn the job of a comma with the words 'and,' 'or,' 'which,' 'because,' and 'but.'


Separating Parts of a Series

A comma is used with parts of a series. When writing a list, or series, of three or more items, commas are used to separate the words and make the meaning clearer.

  • The children played with frolicking bunnies barking dogs and cats.

When you read this sentence, it could be interpreted that the dogs and cats were barking.

  • The children played with frolicking bunnies, barking dogs, and cats.

This sentence, written with commas between each item and before the word 'and,' gives the reader a visual image of the three listed animals.

  • Did she find the flour spice or fruit?

This sentence, written without commas, refers to an ingredient called flour spice. I have never heard of that, have you?

  • Did she find the flour, spice, or fruit?

When we add the commas between the ingredients and before the word, it makes the meaning of the sentence more understandable.

Oxford Comma

It's important that we also take note of a common term you may hear: the Oxford Comma. The Oxford comma is the final comma in a series. For example:

  • Please bring me milk, doughnuts, and napkins.

Let's try again without the comma after doughnuts, also known as the Oxford comma.

  • Please bring me milk, doughnuts and napkins.

The sentence makes sense with and without the Oxford comma. That is why Americans don't always use it when writing a list. It is important to know what the expectations are when applying the Oxford comma, since most teachers/professionals have differing ideas on the Oxford comma's use.

Separating Independent Clauses

The words 'but,' 'and,' and 'or' are a few words called coordinating conjunctions. A coordinating conjunction is used to connect words, phrases, and clauses. There are seven coordinating conjunctions, but for the purpose of today's lesson we will focus on the words 'but,' 'and,' and 'or.'

A comma is used to separate independent clauses in a compound sentence. An independent clause is a group of words with a subject and a predicate. It expresses a complete thought and can stand alone as a sentence. A compound sentence is a sentence with at least two independent clauses. Let's take a look at an example.

  • I like to go the amusement park.
  • My favorite ride was broken.

Both of these sentences are independent clauses, because they have a subject (a person or thing doing the action) and a predicate (comments on the subject, what the subject is doing). Let's combine these with a coordinating conjunction:

  • I like to go to the amusement park, but my favorite ride was broken.

These sentences were combined with a comma before the coordinating conjunction 'but,' to help the sentence read smoother. Make sure to place the comma after the first clause and before the coordinating conjunction.

Preventing Confusion

Some writers mistakenly put a comma before the word 'because' every time they write it. It's unusual to need a comma before 'because.' If a sentence could have two meanings, then a comma is used to make the sentence more coherent.

  • I heard that my friend moved because I heard my dad telling my mom.

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