Writers often struggle over the gnarly question of whether to put a comma before the conjunction and and its fellow conjunctions. And is one of seven coordinating conjunctions which are punctuated similarly. These conjunctions spell out FANBOYS: for, and, nor, but, or, yet, and so.
DO Use a Comma
- Put a comma before and when connecting independent clauses. Remember, an independent clause has a subject and a predicate and can stand alone. In the following examples, the independent clauses are underlined.
First we ate breakfast, and then we went to school.
The market is growing, and we will be there to meet the demand.
He studied medicine for 12 years, and now he is a specialist.
DO NOT Use a Comma
- The comma is unnecessary for other uses of and.
He is short and fat.
Hemingway was known for his brisk prose and intense characterizations.
Lions and tigers and bears, oh my! - If you are not connecting independent clauses, do not add the comma.
Note that in these examples, there is one subject and two verbs. In this case, it is not necessary to repeat the subject for the second verb and not necessary to insert the comma. In the examples, the subject is bold; predicates are underlined.
We ate breakfast and then went to school.
We will be there to meet the growing demand.
He studied medicine for 12 years and is now a specialist.
Sometimes Use a Comma
- If the two independent clauses are short, the comma is optional. Include it if it makes the sentence sound better; omit it if the sentence works without it.
Give me the keys and get in the car.
The service was great and the food was lousy.
- What about the comma in a list?
The comma before the and on a list of items is known as the serial comma or the Oxford comma. Although great battles have been fought about whether or not to use this comma, the fact is that it is generally a matter of personal choice, like deciding whether to use gardenia shampoo or whether to use jalapeno ketchup on your french fries.
BOTH are correct:
Please buy pens, pencils, paper, and tape.
Please buy pens, pencils, paper and tape.
The only time you absolutely must use a serial comma is when it would affect the meaning of your sentence. For example, in a legal document, you might find the sentence:
I bequeath my estate to my children, Helen, Henry, Harold and Hilda.
How is the money divided? Do Helen and Henry each get a third while Harold and Hilda split a third? Or does each child get a quarter? This ambiguity would be eliminated by writing:
I bequeath my estate to my children, Helen, Henry, Harold, and Hilda.
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In short, you will usually insert a comma before and when the word connects two clauses that could stand alone. In other situations, it is not required. When and connects words, not clauses, do not insert a comma.
And by the way, here is one other point about and: The world will not end if now and then you start a sentence with and. Just don’t put a comma before it.