The Oxford comma, also known as the serial comma, is the final comma in a series. You’ll find people have a strong opinion about using the Oxford comma.
If you’re unsure of when to use the Oxford comma, it helps to consider what variety of English you speak and what style guides you use — because, basically, it comes down to consistency.
What is the Oxford Comma?
The Oxford comma comes right before the coordinating conjunction in a series.
Ex: To complete the project, you need a wrench, hammer, and nail.
This comma is technically not required in a series. The above example would also be correct written as the following:
Ex: To complete the project, you need a wrench, hammer and nail.
But many people strongly feel the Oxford comma should be required. Those who advocate the comma argue that it prevents ambiguity in a sentence. Consider the following examples:
I like my brothers, Tony, and Zachary.
I like my brothers, Tony and Zachary.
In the first example (with the Oxford comma), we understand that the speaker likes his or her brothers. We also understand the speaker likes another person named Tony and another person named Zachary. This sentence is referring to at least four or more people.
The second example (without the Oxford comma) causes some confusion because we’re not sure if Tony and Zachary are the speaker’s brothers. In this case, the Oxford comma is necessary.
What Variety of English Do You Speak?
American English usually calls for the Oxford comma. British English rarely uses the Oxford comma. Consequently, most American English style guides recommend the Oxford comma, while most British English style guides discourage using the comma. However, if using the Oxford comma clears up confusion, experts advise its use regardless of what variety of English you speak. Be sure to check the style guide you’ve been asked to use for your writing projects.
What If the Style Guide Doesn’t Mention the Oxford Comma?
If the style guide you’re using doesn’t have a preference about the Oxford comma, then you get to choose. The key is being consistent with your use of this comma. If you use the Oxford comma in your opening paragraph, then you should use the oxford comma throughout your entire piece. The same goes for leaving out the Oxford comma.
Don’t fret over the Oxford comma too much. Follow the appropriate style guide for your project and consider the variety of English you use. Then be consistent. That’s all there is to it.