How to Use Commas: The 8 Rules That Matter

The comma is the most-used punctuation mark in English and the one people are least sure about. Luckily, a handful of rules cover nearly every situation, and the rest is style.

1. Separate items in a list

Use commas between three or more items: We need flour, eggs, butter and sugar.

The comma before the final and is the serial (or Oxford) comma. American style guides usually require it; many British publications leave it out. Either is acceptable if you're consistent, but add it whenever leaving it out could confuse: I'd like to thank my parents, Ana and Tom could mean your parents are called Ana and Tom. My parents, Ana, and Tom lists three people.

2. Join two independent clauses with a conjunction

An independent clause can stand alone as a sentence. When you join two of them with a coordinating conjunction (for, and, nor, but, or, yet, so), put a comma before the conjunction:

The rain stopped, and the match restarted.

If the second part can't stand alone, skip the comma: The rain stopped and then started again.

3. After an introductory word, phrase or clause

Put a comma after something that comes before the main clause:

• However, the score was still close.
• After the final round, we compared notes.
• If you hold a blank tile, keep it for a bingo.

Very short introductory phrases can go without: In 2024 the rules changed. Add the comma if it helps the reader.

4. Around extra (non-essential) information

If you could delete a phrase and the sentence would still make sense and mean the same thing, surround it with commas:

My brother, who lives in Leeds, plays every Sunday. (You have one brother; where he lives is a bonus fact.)

If the phrase identifies which one you mean, it is essential and takes no commas:

The player who scored highest wins a prize. (Remove who scored highest and the meaning changes.)

5. Before and after direct address

When you speak to someone by name, separate the name: Thanks, Sam. / Sam, it's your turn. Compare Let's eat, Grandma with Let's eat Grandma. That comma is doing serious work.

6. Between coordinate adjectives

If two adjectives each describe the noun independently, separate them: a long, difficult puzzle. Test: can you swap them, or put and between them? A difficult and long puzzle works, so use a comma.

If the adjectives can't be swapped, don't: a bright red car (not a red bright car).

7. With dates, places and numbers

• On March 4, 2026, the tournament began. (US date style: commas around the year.)
• She moved to Austin, Texas, last spring.
• The board has 15,000 tiles in storage. (Thousands separator.)

8. Before or after a quotation

She said, "Play the Q." / "Play the Q," she said. In American English the comma goes inside the closing quotation mark; British style usually places it according to meaning, but inside is common for dialogue.

The comma splice: the mistake to watch for

A comma splice joins two complete sentences with only a comma:

The game ended, everyone went home.

Fix it in one of four ways:

1. A full stop: The game ended. Everyone went home.
2. A conjunction: The game ended, and everyone went home.
3. A semicolon: The game ended; everyone went home. (See semicolons and colons.)
4. Make one clause dependent: When the game ended, everyone went home.

Commas you don't need

• Between a subject and its verb: The highest-scoring word in the game, was QUIXOTIC.
• Before because at the end of a sentence, in most cases: We lost because we passed too often.
• After such as or before the first list item: Games such as, Scrabble and Boggle.

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