Commas and Comma Splices

Commas are one of the most widely used punctuation marks in the English language. They are used in several places for different reasons.

1. Use a comma before the eight coordinating conjunctions (and, or, so, but, nor, yet, for, although).

  • He came early, but she came late.
  • I was ready to leave, but he didn't see my ride.
  • I was hungry, and I wanted to eat.
  • It was raining, so I walked him to the bus.

2. After a subordinate clause that comes before a main clause. Subordinate clause: has a subject and a verb, but is not a complete sentence. Subordinate clauses are often used to add information to another clause, especially to tell about specific circumstances.

  • When I'm hungry, I go to my favorite restaurant.
  • Despite the fact we were tired, we stayed up to watch a movie.

3. Around extra information that does not include a verb.

  • New Hampshire, a state with many tall mountains, is my home.
  • My son, Rick, is home from college.
  • My father, a good doctor, took care of me when I broke my arm.

4. With non-defining relative clauses. Similar to #3, non-defining relative clauses give additional information about something, but does not define it.

  • Professor Smith, who teaches the evening class, is at home.
  • Central Park, which was built by Olmsted, is one of the world's most venerated parks.

5. Between two elements or items in a list.

  • I like bananas, pears and peaches.
  • I took a several classes my first semester in college: English 1010, Theatre 1020, Biology 1010 and Math 1050.

Comma splices, sometimes called "run-on sentences" or "fused sentences," are a common problem for beginning (and even advanced) writers. Comma splices most often occur when the writer tries to add two sentences together by simply adding a comma. The problem is that the sentence does not work unless a semicolon is used or a coordinating conjunction. Another option is to make each clause into separate sentences.


Incorrect: I saw David outside of class, he gave me a book.
Correct: I saw David outside of class; he gave me a book.

Incorrect: She told me to look outside, I didn't see anything.
Correct: She told me to look outside, but I didn't see anything.

Incorrect: I looked outside, the mailman was nowhere to be found.
Correct: I looked outside. The mailman was nowhere to be found.

Note from the examples that there is no single way to fix comma splices. Which solution is chosen depends on the rest of the paragraph surrounding the sentence, and what type of effect you want to create. For example, a series of short sentences might be irritating in an information paper, but creates a certain mood in a short story.


Last modified: Thursday, 14 June 2012, 4:19 PM