How to Use Commas

Although they are meant to be helpful, commas can be a major pain. They aren't as obvious as periods, but luckily, they aren't as elusive as quotation marks either. The rules are tricky and tough, but these guidelines and examples should be easy to use and simple to remember.

Instructions

1. Add a comma if you are introducing a sentence with a word or phrase. For example: "However, the apples were bruised and moldy." Another example: "As a matter of fact, the bees produced plenty of honey this year."

2. Use a comma to distinguish two complete thoughts in one sentence. For example: "She was over an hour late, but the concert had not started." In this sentence, "She was over an hour late" and "the concert had not started" are separate thoughts that relate to one another. Join them with a comma. A good test is to see if you can make two separate sentences. If you can, use a comma. If one of the two thoughts does not make a complete sentence, you do not need a comma.

3. Place a comma before conjunctions. Conjunctions are joining words. The most common are: for, and, nor, but, or, yet and so. However, if the sentence does not have two complete thoughts, you do not need a comma. Here are two sentences that demonstrate this. Sentence 1: "Apples or bananas are good ingredients for a fruit salad." Sentence 2: "Sliced apples are good in a fruit salad, or you can serve them whole." In Sentence 1, the comma is not needed because you are simply mentioning two items. There is only one thought. In Sentence 2, the comma is necessary because you are connecting two thoughts.

4. List items in a sentence by including commas. For example: "The baseball game was hot, sticky, and tiring." When you have short lists, the last comma before the conjunction is optional. Therefore, this is also correct: "The baseball game was hot, sticky and tiring." This is the trickiest part about comma use. Some people believe that a comma should always be placed before the conjunction, while others believe that the comma should be left out. Double-check with your teacher or editor on this rule.

5. Utilize commas when connecting long lists. The guidelines in Step 4 refer to short, simple lists. When you connect longer lists, always include commas, even before the conjunction. For example: "A dedicated employee arrives on time, stays late, eats lunch at his desk, and puts his career before anything else." In this sentence, the list was long and complex. Use commas to separate every item, including the final one, which was, "and puts his career before anything else."

6. Separate extra information or "side thoughts" with two commas. For example: "Sandy Smith, a 39-year-old mother of two, has won the Iowa State Lottery jackpot." The main thought of this sentence is that Sandy Smith won the lottery. However, to make the sentence more interesting, more info is given to the reader. Since the sentence would stand alone without this extra information, separate it with commas. Another example: "The child was hot, not freezing, even though the temperature was below zero."

Tips & Warnings

• Sometimes a sentence with two complete thoughts does not have a conjunction. Adding a comma usually results in an error. For example: "Mary put on sunglasses, she needed a break from the sun." Even though there are two thoughts in this sentence, the comma is not strong enough to hold the two parts together. Switching to a semi-colon is an easy fix: "Mary put on sunglasses; she needed a break from the sun." Another option is to insert a connecting word: "Mary put on sunglasses because she needed a break from the sun."

• Insert a comma in a sentence to demonstrate contrast. For example: "He wanted vegetables for dinner, not red meat."

• If you are writing for a publication or company, they may have a specific policy regarding comma use. Check with your editor to make sure you are following the proper guidelines or style guides.

• You do not always need a comma in a sentence with multiple verbs. This is a common mistake made by writers. For example, the following sentence is incorrect. "I ran to my house, and locked the door." There are two verbs (ran, locked) and a conjunction (and), but you do not need a comma. The correct version of this sentence is as follows. "I ran to my house and locked the door." Remember--try the thoughts you are separating with a comma as two complete sentences. If they don't stand alone, you don't need the comma.