In Commas in a List you put commas between things in a list. Now we can say it more exactly. A series is three or more words, phrases or clauses in a row, joined at the end by and or or. Commas mark the border between one item and the next, the way your voice pauses when you read a list aloud.
Key idea
Put a comma after each item in a series except the last. The comma just before and or or is called the serial (or Oxford) comma, and it is a style choice.
| Style guide | Comma before the last and? |
|---|---|
| Chicago Manual of Style | Yes |
| MLA Handbook (most English classes) | Yes |
| APA Publication Manual | Yes |
| AP Stylebook (most newspapers) | Usually no, unless leaving it out would confuse |
Why it works
Without commas, the items blur together: “We bought pears plums peaches and grapes” makes the reader sort out the words. Back in 1918, William Strunk’s second rule said it plainly: “In a series of three or more terms with a single conjunction, use a comma after each term except the last.”
Worked example: A series of actions
Add commas: “Mia can sing dance and play the drums.”
- Find the items: sing / dance / play the drums. There are three, so it is a series.
- Put a comma after each item except the last.
- With the serial comma: “Mia can sing, dance, and play the drums.”
- Without it (AP style): “Mia can sing, dance and play the drums.”
Answer: Mia can sing, dance, and play the drums. (Leaving out the comma before and is also standard.)
Worked example: When the last comma prevents confusion
“For lunch we had soup, salad and macaroni and cheese.”
- The items are soup / salad / macaroni and cheese. The last item has its own and.
- Without the serial comma, “salad and macaroni and cheese” runs together.
- Here even AP style adds the comma.
Answer: For lunch we had soup, salad, and macaroni and cheese.
Common mistake
Being told the serial comma is simply right or simply wrong. It is a choice between two standard styles; school papers in MLA style use it. The real errors are a comma after the last item (“apples, and lemonade, for the picnic”) and a comma between only two items (“sandwiches, and apples”). Two items need no comma at all.