In a list of three or more items, separate items in the list with commas. Include a comma along with the conjunction before the last item in the list.

• I have a laptop, a pen, and a book in my backpack.
• Do you want coffee, tea, or orange juice?

Use a comma along with a coordinating conjunction to join two or more independent clauses into a single sentence.

• There was a cat asleep on the printer, so I couldn’t print my document.
• Vegetables are very nutritious, but many people don’t eat enough of them.

When your sentence begins with an introductory word, phrase, or clause, use a comma to mark the beginning of the main clause of the sentence.

• However, this plan seems unlikely to succeed.
• After work, I like to meet my friends for coffee.
• Even though it’s hot, the dogs still want to play outside.

Use a pair of commas to set off additional information that is not essential to the sentence.

• Most people, even introverts, need more social interaction than they can get while working remotely.

When your sentence calls out the person you’re speaking to by name, title, or description, use a comma or a pair of commas to set that off from the rest of the sentence.

• Sam, did you bring the snacks?
• Did you bring the snacks, Sam?
• Did you, Sam, bring the snacks?

Commas in dialogue

• The captain said, “The ship sets sail at high tide.”

Comma between the city and state

• Chicago, Illinois
• Pittsburg, KS

Comma in the Month Day, Year, date format

• July 17, 2023      

Commas between the hundreds and thousands places

• 1,000   
• 92,528    
• 9,578, 443