When you first grasp the rules of how to use semicolons, you'll be tempted to overuse them. However, the semicolon won't be necessary most of the time. Nonetheless, here are the rules:
A semicolon can be used
- To join two independent clauses that make sense when combined.
Kate liked to take long walks on the beach; Alex preferred building sandcastles.
- To join two independent clauses along with a joining word.
Kate liked to take long walks on the beach; however, Alex preferred building sandcastles.
Note: Since "however" is NOT a conjunction, it cannot be used only with a comma to join two independent clauses.
Keep in mind, a period could be used in either of the above examples. If you choose to use semicolons to join clauses, you're really making a stylistic choice rather than a grammatical one. And don't forget, you shouldn't capitalize the first letter of the word that follows a semicolon unless it is a proper name.
- To separate items in a list when one or more of the items contains a comma.
Tracy brought her pet hamster, Pickles; her three hundred CDs; and her antique, mahogany lounge chair to her dorm room.
Since two items in this list contain commas, using commas as a separator will cause confusion for the reader.
Note: Do not use a semicolon to join a phrase or incomplete sentence to an independent clause.
Wrong: Alex liked to build sandcastles on the beach; which was how he spent last summer.
Correct: Alex liked to build sandcastles on the beach, which was how he spent last summer.