Look, I understand that commas are one of the trickiest punctuation marks. However, the fact that many people these days forget – or even worse, ignore – the basic comma rules makes me want to die a little.
Yes, I know, we could nitpick for hours about how language is an ever-changing, amorphous being. But here’s the gist: Content with correct grammar makes you look smart and competent; content without correct grammar sends a warning sign to your clients.
So to beef up your blog, e-mail blasts, or website content, I’ve compiled a few comma rules and when to use them. If any time you’re confused about a term I use, check out Jana’s post about parts of speech.
Within a series: When you have a list of three or more items, place a comma after every item that occurs before “and.”
Examples: HankMed consists of Hank, Evan, and Divya. The company treats rich, famous, and average people.
Pro Tip: The Oxford comma has been disappearing from publications because newspapers don’t want to spend the extra ink on it. Just because they are taking the easy way out doesn’t mean you should. The extra comma lets the eyes focus on each item.
Around degrees and titles: Degrees like “PhD” and titles like “CEO” should be separated from the person’s name with commas.
Examples: The founders of HankMed were Hank Lawson, MD, and Evan R. Lawson, CFO. Before becoming Evan R. Lawson, CFO, Evan was Evan R. Lawson, CPA.
Pro Tip: Titles and degrees are well-earned, so give them the distinction they deserve by setting them apart with commas. However, generational suffixes like “Jr.,” “Sr.,” or roman numerals do not get commas.
Connecting two independent clauses: If you have two clauses that could stand on their own but sound better together, connect them with a comma and coordinating conjunction.
Examples: Diyva was engaged to marry a rich man, but she prefers being Hank’s physician assistant. She’s amazing at her job, and HankMed is lucky to have her.
Pro Tip: The coordinating conjunctions (and, but, for, nor, yet, or, so) are your best friends.
Before or surrounding the name of the person addressed: When you are directing a statement at a particular person, split them from the rest of the sentence.
Examples: “Wow, Evan, these imprinted promotional products look great!”
“Thanks, Divya! Hank, didn’t they do a great job?”
“Sure. Great job ordering them, brother.”
Pro Tip: Names count, but so do titles. Separate titles like “sir” or “doctor” with commas as well.
Parenthetical elements: If you have information that further explains your subject, set it off with commas.
Examples: The EKG machine, which was in the back of Divya’s van, was essential to Hank’s diagnosis. The patient, a famous actress, was complaining about chest pains.
Pro Tip: In the second example, “a famous actress” is called an appositive. Sometimes appositives are so closely related to the subject that with a little placement change, they can forgo a comma. Turn “The doctor, Hank, was worried.” into “Dr. Hank was worried.”
Contrasting phrases: When linking together two phrases that contradict each other, insert a comma to distinguish the difference.
Examples: Hank was annoyed when Evan brought him antibiotics, not painkillers. He stressed leaving the doctoring to him, not his brother.
Pro Tip: Don’t toss in a comma for things that agree. “Hank needed antibiotics and painkillers” is correct.
Multiple coordinate adjectives: When you have many adjectives, break up the list with commas.
Examples: Hank noticed that his patient had a red, swollen bruise. Divya pulled antiseptic out of Hank’s old, worn doctor’s bag.
Pro Tip: If you can slip an “and” or “but” between the adjectives, or you can reverse the order, a comma belongs there. “Little old lady” would not have commas because you wouldn’t say “little and old lady.”
Statements and questions: When you make a statement and then want to ask a simple question about said statement, use a comma to separate them.
Examples: HankMed is the best concierge medicine service, don’t you think? Royal Pains doesn’t come back until the winter, right?
Pro Tip: Careful that you don’t link to questions that could stand on their own. “Divya is the best, when do you think she’ll find her true love?” is not correct.
The one general rule when it comes to commas is: if not having it will potentially confuse your reader, you probably need it. This, like all grammar rules, is not an exact science, but it will serve you well in times of desperate need.