1. When Do I Use a Comma? Quick Rules for Comma Usage

2. Rule #1
Before a coordinating conjunction (for, and, nor, but, or, yet, so) that separates two independent clauses (complete thoughts).
EX. I have no homework in math, but I have hours of reading for English class.

3. Rule #2
After an introductory word, phrase, or clause that comes before the main sentence.
EX. Despite immigrant’s high hopes, their illusions were often shattered.
EX. Suddenly, I’m not so excited about seeing Bob this weekend.
EX. Since the new system was implemented, payroll has been processed 25% faster.

4. Rule #3
Use commas around words, names, phrases, and clauses in the middle of a sentence when they aren’t essential to the meaning of the sentence.
**This is also known as an “interrupter.”
EX. Numerous studies, however, have shown that negative reinforcement affects self-image.
EX. Karl Marx, a prominent sociologist, believed he could use his influence to change the world.

5. Rule #4 Use commas between items in a series.
EX. The frigid, snowy, windy day was typical of Minnesota in January.
EX. Three reasons for the closing were insufficient enrollment, poor instructional materials, and inadequate funds.

6. Rule #5 Use commas before and after a quotation within a sentence.
EX. “Cooperation,” the president said, “must exist if the country is to prosper.”
EX. The band leader said, “Once the basic drill is learned, we’ll work on more complex maneuvers.”

7. Rule #6 Use a comma before an afterthought or contrasting element.
EX. The War of 1812 was vitally important for Canada, far more important than it was for Britain.
EX. We must judge the society as a whole, not for its individual parts.

8. Rule #7 Use commas to set off geographical names, items in dates and professional titles.
EX. Abraham Lincoln was born on February 12, 1809, in a log cabin near Hodgenville, Kentucky.
EX. Stephanie Glenn, Ph.D., will be the main speaker at the banquet.