Compound Sentences and the Comma vs. the Semicolon

When joining two independent clauses (or two sentences, or two complete thoughts), you’ll need to determine whether to use a comma or a semicolon.

When using a comma, one of these coordinating conjunctions must be used: and, but, for, nor, or, so or yet. The comma will be placed before the conjunction used. Examples of correct comma usage:

• I’m going to the zoo, and I will see the gorillas.
• Chocolate is my favorite ice cream flavor, but I sometimes like eating the strawberry ice cream flavor.
• Jenny’s mother saw her come home late at 2:00 a.m., so Jenny is grounded for the next two weeks.

When using a semicolon, a coordinating conjunction is not needed to join two independent clauses. Examples of correct semicolon usage:

• I’m going to the zoo; I will see the gorillas.
• Chocolate is my favorite ice cream flavor; I sometimes like eating the strawberry ice cream flavor.
• Jenny’s mother saw her come home late at 2:00 a.m.; Jenny is grounded for the next two weeks.

When using a conjunctive adverb (however, therefore, nevertheless, etc.), a semicolon can also be used. Examples of correct semicolon usage with conjunctive adverbs:

• Jenny arrived home late; therefore, she is grounded for the next two weeks.
• Chocolate is my favorite ice cream flavor; however, I sometimes like eating the strawberry ice cream flavor.