Commas with Clauses and Phrases

Commas are used between independent clauses (ones which could stand alone as complete sentences). This is done in the same way that commas are used to separate items of a series: Her balloon was red, shiny and round.

• He inflated his balloon, he sucked some helium out of it, and he began to imitate 'The Chipmunks.'

A comma comes between two independent clauses joined by coordinating or correlative conjunctions.

• I don't want to go roller skating with you, and I don't want this Pee Wee Herman doll.
• He cooks like Betty Crocker, but my mother still doesn't like him.
• Either Trinai was just being friendly, or she had a crush on Chamique.

A comma is needed after a dependent clause (one that cannot stand alone as a complete sentence) that precedes an independent clause. These types of dependent clauses are usually introduced with subordinating conjuctions.

• Although Mohammad's moustache needed cleaning, he decided to save his breakfast crumbs for an afternoon snack.
• Unless you plan on walking home, you'd better clean up your attitude.

Commas set off appositives--words, phrases, or clauses that follow a noun or pronoun and identify it--if they are nonessential to the meaning of the sentence.

• Old Lady Hamilton's house, a wood and brick structure on a 13 acre plot, came accessorized with windchimes hanging above all the toilets.
• Grouchy Old Enn's first novel, Butternut Squash and the Temple of Prunes, was a runaway bestseller.
• Ernesto handed me a bundle of flowers, wilted poppies and drooping tulips.

Commas are omitted if the appositive is essential to the meaning of the sentence.

• The Beatles' album Revolver is renowned for its cover artistry.
• Marguarite Duras' novel "The Lover" is highly erotic and a lot of fun to read.

A comma does not set off a dependent clause that follows a main clause if the dependent clause is essential and would alter the meaning of the main clause.

• I'll go to the country bar with you if you promise to wear your alligator boots.

A comma precedes a nonessential clause that follows a main clause. This type of clause would not alter the meaning of the main clause if it was omitted.

• Geri agreed to give me a ride, although she doesn't like me very much.

Commas set off nonessential phrases and clauses that give descriptive information that doesn't alter the meaning of the sentence.

• Karla, who loves to tap dance, bought three new pairs of shoes and a black bow tie.
• The weather today, unseasonably warm, was causing my usually poufy hair to unpouf.

No comma is used with an essential clause.

• The men who wear black socks like to pull them up to their knees.
• Anyone who laughs at that joke is a complete moron.

A comma should set off a parenthetical clause, phrase, or word that is logically close to the rest of the sentence. Parenthetical elements less logically related to the rest of the sentence should be set off instead by dashes or parentheses.

• This movie, I must say, is completely devoid of plot.
• I was going to the house (the blue one at the corner), and I saw a man wearing a short suede skirt.

A comma should offset two or more complementary or opposing phrases that refer to a single word that follows them.

• My thick, though at the same time fine, hair does not respond well to perms or color treatments.
• My ancient, though nonetheless reliable, Chevy will outrun your Porsche any day.

Opposing, or antithetical, interdependent clauses should be set off by a comma.

• The more she studied, the less she knew.
• The longer I live with you, the less I like the way you fold my shirts.

Short opposing (or antithetical) phrases don't require commas.

The iguana was fat but fast.