Commas
Use commas to indicate where readers should pause for breath in a sentence. Use your common sense and follow these tips on when – and how – to use them.
Avoiding ambiguity
- Let's eat, Grandma!
- Let's eat Grandma!
Enough said.
Linking adjectives
Use between qualifying adjectives (ones that describe the qualities of a person or thing):
Beryl is a large, friendly, greedy llama with long, yellowing teeth.
Don't use between classifying adjectives (ones that place people and things into categories or classes):
Beryl is a 14-year-old South American llama.
Don't use a comma between a mix of these two adjectives:
Beryl is a large South American llama with yellowing 14-year-old teeth.
Linking transitional words
With words like "however", "though", "on the contrary", "nevertheless", "on the other hand", "conversely", "likewise", "similarly", "of course", "in addition".
Use a comma straight afterwards if they start a sentence:
Of course, I could have just one more sandwich.
However, they were already running late.
And surrounding them in the middle of a sentence:
It was far too late, though, to worry about the meeting now.
However, even though it's tempting, don't use a comma after a time-based adverbial phrase:
After eating sandwiches all afternoon she was full.
Listing items
Use between items in a list:
I need some eggs, flour, milk and red wine.
Note that there is no comma after the second-last item in the list above. If it would help to prevent confusion, add a comma here:
I need some red wine, peanut butter, and butter.
This is sometimes referred to as the Oxford comma.
Surrounding clauses
Use to surround clauses beginning with “which” or “who” that you can remove without losing the meaning of the sentence:
The llama, which had previously been asleep, was now eating from my backpack.
Use to surround a word or phrase which you can remove without losing the meaning of the sentence:
Sir Clive Granger, a University of Nottingham graduate, won the 2003 Nobel Prize for Economic Science.
But don't use one where the defining information is at the start of a sentence.
University of Nottingham graduate Sir Clive Granger won the 2003 Nobel Prize for Economic Science.