726. When to Use a Comma with And

A compound sentence is sometimes made using the conjunction and along with a comma. In order for the sentence to be compound, there must be two complete thoughts joined by the conjunction and. Look at these examples of a compound sentence:
Today is Monday, and we have school.
I will rake the leaves, and you can mow the lawn.
John likes dogs, and Sarah likes cats.
In every one of these sentences, the words after and form a complete thought, so we must put a comma before and.

Be careful to check that there are two complete thoughts before putting a comma with the word and. We can only use a comma with and when there is a complete thought on both sides of and. These sentences do not have a complete thought after the word and. These sentences do not use a comma after and.
Today is rainy and cold.
I will rake the leaves and mow the lawn.
John likes cats and dogs.
In each of these sentences, the words after the word and do not form a complete thought, so we do not use a comma with and. These sentences are not compound sentences.

Only use a comma with the conjunction and when joining two complete thoughts together to make a compound sentence.

▶It’s your turn. Decide – does this sentence need a comma with and? Dad likes to read and work crossword puzzles. I hope you figured out that this sentence does not need a comma.