TECHNICAL ACCURACY

How to use commas

Despite what you may have been told, commas are not really for pauses. Commas are there to mark out parts of a sentence, like those described in the guide to writing sentences, though they often coincide with pauses, which is why people use this simplified explanation to help younger children understand them. There are roughly seven situations in which commas should be used. Be warned: this is gets a bit complicated.

This guide is part of the Technical accuracy series:

  1. Why technical accuracy really matters

  2. How to avoid common but basic SPaG errors

  3. How to use apostrophes

  4. How to use commas

  5. How to use semi-colons

  6. How to demarcate paragraphs

Situation 1 - this is the most common use of commas and is similar to Situation 2, below

Use commas around non-essential words and phrases, including relative clauses or adjuncts, like similes or participle phrases, which can be at the start, end or middle of the sentence. If these words are dropped, the sentence will still make sense and keep its basic meaning. This is a form of parenthesis and sometimes other punctuation can be used instead, such as brackets or dashes.

  1. My teacher, Mr. Smith, is a great singer.
    (My teacher is a great singer.)

  2. The pillow, soft and fluffy, cushioned my head as I napped on the hammock.
    (The pillow cushioned my head as I napped on the hammock.)

  3. The elephant, which is massive, careened into my garden and straight through the empty hammock.
    (The elephant careened into my garden and straight through the empty hammock.)

  4. No wonder she moves with gingerly concern, like a child who's been told not to spill something on herself.
    (No wonder she moves with gingerly concern.)

  5. Harriet cut through the freight yard towards the woods, hopping over the tracks and humming to herself.
    (    Harriet cut through the freight yard towards the woods.)

  6. I did use a comma before the co-ordinating conjunction in the previous sentence, though, because it felt right there.
    (I did use a comma before the co-ordinating conjunction in the previous sentence because it felt right there.)

  7. This is the most common use of commas and is similar to Situation 2, below.
    (This is the most common use of commas and is similar to Situation 2.)

Situation 2 - similar to Situation 1

A comma should be used when you start a sentence with a subordinate clause, an adverbial phrase (including participle phrases) or an introductory word.

  1. While my wife floats around in zero gravity, I have to paint the new fence.

  2. After I’d eaten my dinner, I went out to scare away the elephant.

  3. At the first sign of trouble, elephants flee.

  4. However, they create even more mayhem when frightened.

  5. Destroying everything in its path, the elephant ran through the small Suffolk town.

  6. Horrified, her heart pounding, Harriet began to run.

Situation 3

A comma should be used to separate direct speech from the rest of a sentence.

  1. “You need to do the washing-up while I scare off the elephant,” I told Johnny.

  2. Johnny said, “Alright.”

Situation 4

A comma should be used before a coordinating conjunction if it connects two main clauses (clauses that are capable of standing alone as a sentence).

  1. Johnny wants a pet elephant, and my wife wants a wolverine.

  2. I don’t like animals, but my opinion doesn’t count for much in this house.

If the two main clauses are very short, it is acceptable – for style purposes – to leave out the comma. So: I am a bus driver and my wife is an astronaut would be acceptable.

In Situation 2, above, I did this very thing in the following sentence: This is a form of parenthesis and sometimes other punctuation can be used instead. A comma could come after the word ‘parenthesis’ here, but I prefer it without the comma, so I’ve not used one in that sentence. I did use a comma before the co-ordinating conjunction (‘so’) in the previous sentence, though, because it felt right there. Comma use is complicated…

You should not use a comma when the parts connected by the coordinating conjunction can’t stand alone. For example:

  1. Johnny wants a pet elephant and a wolverine. (No comma required.)

  2. Johnny wants to ride his elephant and stroke his wolverine. (No comma required: ‘stroke his wolverine’ cannot stand alone as a sentence.)

Situation 5

Commas should be used whenever you include direct address. This is when a person’s name or title is used in a sentence to actually address the person.

  1. Well done, Sally! You got all your commas right in this exercise.

  2. I don’t know about you, Peter, but I’m getting tired of all these references to elephants and wolverines in these examples.

Situation 6

Commas should be used between coordinate adjectives. They are coordinate if they sound natural when they are either reversed or joined by and.

  1. The road dwindled into a rough, narrow path.

  2. The road dwindled into a narrow, rough path.

Situation 7

A comma should be used when you are writing a list of at least three things. You probably knew this one already, so it was left until the end.

  1. My wife likes animals, space stations and The X-Men.

  2. In a state of fear, our neighbour’s elephant ran through the park, past the school and onto the motorway.

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