When To Use Commas

Comma – Punctuation mark

Commas reflect pauses in speech.

A listing comma is used to separate items in a series or list. In British English, the last two items in a list are not usually separated by a comma unless these are long.

• The Three Musketeers were Athos, Porthos and Aramis.
• I went to China, Japan, Malaysia and Singapore.

A joining comma is used to join two complete sentences into a single sentence. It is usually followed by a connecting word like and, or, but, while or yet.

• We can go swimming, or we could stay here.
• I decided to come home earlier than I had planned, and the others spent the evening at the local disco.

A gapping comma is used to show that certain words have been omitted instead of repeated.

• Jane decided to order the home-made steak pie and Alice, the duck special. (The omitted words are decided to order.)

When subordinate clauses begin sentences, they are often separated by commas.

• After I left school, I went to London.

If words or expressions interrupt the normal progression of a sentence, we usually separate them off by commas.

• John, however, did not turn up.
• We were, believe it or not, in love with each other.

We use commas to mark off a noun or phrase in apposition.

• Milton, the great English poet, was blind.
• Paul, the apostle, was beheaded during the reign of Nero.

Commas are used to mark off a participial phrase from the rest of the sentence.

• Driven by rain, we took shelter under a tree.
• Caesar, having conquered his enemies, returned to Rome.

A non-defining relative clause is separated from the rest of the sentence by commas.

• Sailors, who are generally superstitious, say it is unlucky to embark on a Friday.