I am grateful for the comma, a versatile and often controversial punctuation mark that helps us create clarity in our written communication.
Here are seven ways the comma can help you write more clearly:
1. Set off words in a series: “The soup recipe called for chicken stock, carrots, squash and kale.” Note that there is no comma preceding the conjunction and. In a simple series, it is not necessary to include that final comma. You may, if you wish. In a series that is complex or where the lack of a comma could create ambiguity, include it. “The soup recipe called for vegetable broth, carrots, diced onions, and rosemary.” Without the comma, a cook might wonder whether or not to dice the rosemary.
2. Separate an introductory word or phrase in a sentence: “Yes, I've been thinking about soup as the weather cools.” “Well, how long should I simmer the stew?” Yes, you need a comma after well. I have seen it abandoned far too often lately. “Delving deeper into her cookbooks, she found eight recipes for kale and sausage soup.” The Associated Press Stylebook says that if the meaning is clear, the comma is not needed after the introductory word or phrase. “Finally the bus arrived.” The Blue Book of Grammar and Punctuation says a comma is optional if the phrase has fewer than three words. In any case, use a comma if it helps reduce or eliminate ambiguity. Consider, “On the hillside above the dogs ran free.” A comma after “above” would make clear where the dogs were running.
3. Separate two adjectives when the word “and” can be inserted between them: “She is a talented, creative chef.” No need for a comma if you can’t say the sentence with and. However, if the adjective is part of a noun phrase, you do not need a comma before it. “She is a talented executive chef.” “I wore a fake fur coat to the party.”
4. Set off expressions interrupting sentence flow: “He is, you may recall, rarely late for dinner.”
5. Separate independent clauses joined by a conjunction: “I made soup for the party, and the guests enjoyed it.” “She wanted to toast her host, but her boss raised his glass first.” You can omit the comma if the clauses are both short. “I write and she mud-wrestles.”
Do not use a comma to separate independent clauses that are not linked by a conjunction. “You can freeze the dessert or refrigerate it for a week, there are various choices.” Add a conjunction or make it two sentences. You could also use a semi-colon.
6. Separate the city from the state in a document: Use a comma after the state, as well. Some sources said if you use the two-letter capitalized abbreviation for a state, you need no comma. “I lived in the mountains outside Boise, Idaho, for eight years.” “I lived in Boise, ID for 20 years.” I would spell out the state name and follow it with a comma. On addresses on envelopes, no comma is needed.
7. Set off the date in a sentence: “We married on March 15, 2012, in Seattle, Washington.” When part of the date is left out, omit the comma. “We met in June 1998 in Nampa.”