How to Use Commas with Items in a Series
Commas for two items in a series
Do not use a comma if a sentence contains a list of only two items.
- Example: I like apples and bananas.
- Example: I like to paint and sing.
Do not use a comma if a sentence contains a list of only two items, even if each item is described with many words.
- Example: I like apples baked with walnuts and bananas topped with chocolate and whipped cream.
In the above example, no commas are required. Even if many words are being used to describe items in a list, from a grammatical standpoint there are only two items being listed: 1. apples [baked with walnuts] and 2. bananas [topped with chocolate and whipped cream].
Commas for three or more items in a series
Use commas to separate three or more items in a series.
- Example: The café's smoothie flavors are apple, mango, strawberry, and banana.
- Example: The café's smoothie flavors are apple, mango, strawberry and banana.
In the first example, a comma is placed before the last item in the list, and banana. In the second example, a comma is not placed before the last item in the list. Both sentences are grammatically correct. A comma that comes before the last item in a list is known as a serial comma or Oxford comma.
The Oxford comma is used to make sure that lists are not confusing. In the example above, without the use of the Oxford comma, a reader may think that the café sells a strawberry and banana smoothie, when the café actually sells a strawberry smoothie and a banana smoothie.
In MLA style, always use the Oxford comma.
Commas for two adjectives in a series
If two adjectives modify the same word, separate them with a comma only if the adjectives are coordinate. A set of coordinate adjectives are adjectives of equal importance.
- Example: The hot, humid day seemed to drag on forever.
- Example: The humid, hot day seemed to drag on forever.
In the above examples, both pairs of adjectives are coordinate because they modify the same nouns and are of equal importance.
A set of two coordinate adjectives can also be separated by the word and rather than by a comma.
- Example: The hot and humid day seemed to drag on forever.
- Example: The humid and hot day seemed to drag on forever.
If the set of two adjectives are not coordinate, do not use a comma.
- Correct: The juggler used three yellow balls.
- Incorrect: The juggler used yellow three balls.
In the above examples, three and yellow are not considered of equal importance grammatically, so the set of adjectives is not coordinate. Only three yellow balls is correct. Since the set of adjectives is not coordinate, a comma is not used to separate them.
Coordinate adjectives are especially tricky for English-language learners, because proper usage is determined more by context than by hard and fast rules. Refer to the Parts of Speech section for more information about coordinate adjectives.
Commas for three or more adjectives in a series
Use commas to separate three or more adjectives in a series. The coordinating conjunction and may be placed before the final adjective.
- Example: The hot, humid, rainy day seemed to drag on forever.
- Example: The hot, humid, and rainy day seemed to drag on forever.
Both examples above are grammatically correct. Generally, the use of and before the final adjective is more common in both informal and academic writing.
