I took a small break from the blog with all the holiday stuff going on. But I got a request to address comma usage today, so that’s what we’ll focus on. Commas can be tricky for some. You might not be sure when you need one and when you don’t. Some people assume you need a comma anywhere you would pause when speaking, but this is not true. So when do we need a comma? Let’s look at some common rules.
For compound sentences. First let’s talk independent clauses. An independent clause has a subject and a verb and is a complete sentence in its own right. So, for example, “I went to the park today.” It’s a complete sentence. If you add on another independent clause using and, or, but, nor, for, yet, or so, use a comma before the conjunction. “I went to the park today, and I played with my dog.” If you remove the second subject (the I), it’s no longer two independent clauses and you wouldn’t need the comma. “I went to the park today and played with my dog.”
After a prepositional phrase. Prepositions are words like under, over, above, about, around, when, after, on, etc. You need a comma at the end of each prepositional phrase. “When I went to the park, I saw a friend.” “After breakfast, I went to the gym.”
Appositives are another word for renaming a phrase. For example, “My friend, Jenny, is good at math.” My friend and Jenny are the same, just renamed. Or “My mother, the pianist, is an artist.” This does not apply to “that” phrases.
After introductory phrases like finally or however.
For parenthetical phrases. If you have extra information that could be separated from the rest of the sentence by parentheses and still make sense, surround the phrase with commas. “Mary, who is my mother’s best friend, is a painter.”
To address someone. When you address someone or something, you surround the address with commas. “Jenny, did you finish yet?” Or, “How are you, Tim?”
Between two adjectives that modify the same noun where you could use and between them. “She was young and pretty. She was a young, pretty girl.”
In a series of three or more. This is also known as the Oxford comma. Use a comma before the conjunction in a list of three or more. “I want to thank my parents, Einstein, and God.” If you were to take out this comma, the sentence becomes “I want to thank my parents, Einstein and God,” which actually means Einstein and God are your parents thanks to the appositive rule. That’s why this comma should be used for clarification.
For “If” statements. “If you go, be sure to take the dog.” “If you don’t do it, I’ll take away your phone.”
In dialogue. Use a comma before the quote and at the end of the quote if you use any attributions like he said and she said.
She said, “How are you?”
“It’s late,” he said.
To offset negation. “She was young, not old.” “Instead of old, use ancient.”
Use commas around years in dates. You may know you need a comma before the year, but you also need one after the year if the sentence continues. “July 5, 1995, was an important day for him.”
These are the most common rules for comma usage. It may seem tricky at first, but once you’ve familiarized yourself with the rules, it will all make sense. Review this list regularly and happy writing!