Two Rules of Comma Usage

Even though commas are a very useful tool to separate sentences, they are not always used correctly. This article is about how to correctly use commas in sentences.

RULE 1:

The first rule of correct comma usage is to always put a comma before 'and' or 'but' when starting a new independent clause. For example:

INCORRECT:
Bob rode his bike downtown and Jim bought an ice cream approximately ten seconds before Bob hit him with his bicycle.

CORRECT:
Bob rode his bike downtown, and Jim bought an ice cream approximately ten seconds before Bob hit him with his bicycle.

RULE 2:

The second rule of correct comma usage is to NEVER use a comma alone to separate two independent clauses. For example:

("\0" indicates a space)

INCORRECT:
Bob rode his bike downtown, \0 Jim bought an ice cream approximately ten seconds before Bob hit him with his bicycle.

CORRECT:
Bob rode his bike downtown; \0 Jim bought an ice cream approximately ten seconds before Bob hit him with his bicycle.

Instead of a semicolon, you can also use ", and" or stop the sentence there with a period and start a new one, like this:

CORRECT:
Bob rode his bike downtown, and Jim bought an ice cream approximately ten seconds before Bob hit him with his bicycle.

CORRECT:
Bob rode his bike downtown. \0 Jim bought an ice cream approximately ten seconds before Bob hit him with his bicycle.