Everybody knows what a comma is, right? We use them every day whenever we write anything. But did you know that there are plenty of common mistakes that people make when using a comma in a sentence? Sometimes we use them when they aren’t necessary, and sometimes we don’t use them when they are. This guide will take you through what exactly a comma is (so you can understand when to use them correctly), when not to use a comma, and provide you with some common comma mistakes! We’ll also provide a quiz at the end to test your new understanding of commas.

The Comma (,)

What is a Comma?

A comma is a punctuation mark (,) that is used in a sentence to show a pause. It may connect two parts of a sentence or else separate items in a list. Commas are generally used to make a piece of text more reader-friendly, as without them a reader may become overwhelmed by the sheer volume of uninterrupted text.

A comma is used to denote a pause in the sentence, which is shorter than a colon or a semicolon. A comma is used to show the difference between two separate ideas or elements within a sentence. Commas have other usages as well, as they can be used to separate numbers, and write dates.

American vs. British English Use of a Comma

The major difference between American and British English and the use of the comma is with the serial comma (or Oxford comma in the UK). In the U.S. serial commas are most often used in all lists, no matter what. In the UK, however, Oxford commas are only used when the meaning of the items in the list would be unclear. Here’s an example of when both American and British English would use the serial/Oxford comma:

I’m going to the park with my sisters, Kelly, and June. – By using the serial/Oxford comma here, we are making it clear that the author is going to the park with their sisters and Kelly and June. Writing it as ‘I’m going to the park with my sisters, Kelly and June‘ may imply that the sisters are called Kelly and June. So to avoid confusion, we use the serial/Oxford comma.

Below we’ll provide an example in which American writers and British writers might differ in their use of the serial or Oxford comma:

British Example:

I’m going to pick up bananas, grapes, apples and pears. – In British English it would be seen as unnecessary to use an Oxford comma after apples and before pears, because it is obvious that the two are separate items. Remember, British English only requires the use of an Oxford comma if it is otherwise confusing.

American Example:

I’m going to pick up bananas, grapes, apples, and pears. – In American English, a serial comma is often used in all lists, regardless of whether it would make sense without one.

Key Points to Remember When Using a Comma

The key thing to remember about commas in sentences is that they should be used to break up clauses. If you have more than one clause within a sentence, then using a comma is almost certainly necessary (unless you have another more appropriate punctuation mark to replace it).

Linking a subordinate clause that makes little sense without the main clause, should always be done with a comma to show that the two ideas are linked. If you use your subordinate clause within the middle of a main clause, then you ought to use two commas, one before the subordinate clause and one after. And of course, we should always use commas to separate items in a list. Just remember the differences here for the serial or Oxford comma.