How to Use the Comma (,)

NOTE: Punctuation marks only appear in writing, but mimic the pauses, stresses and other ways we have of giving meaning in speech. That is what they are for! Don’t get too caught up in being correct, just try to be clear.

The comma is the most-used punctuation mark in English and, used properly, it will make your writing much easier to read and understand.


Straightaway, let’s look at the previous sentence. I have put commas before and after ‘used properly’ as they form a non-restrictive relative clause. What the XXXX! I’m sorry, you really don’t need to know fancy terms like that – I was just showing off. A non-restrictive relative clause is just extra information, and if you take this extra information out of the sentence the basic meaning won’t be changed. So if I take ‘used properly’ out of the sentence, the meaning is pretty much the same.

Removing a restrictive relative clause will change the meaning of a sentence, like this:

Restrictive (qualifying information):

• The museum which is in the High Street is dedicated to natural history. 
• This sentence means that there is more than one museum and that the one I’m talking about is in the High Street.
• Non-restrictive (extra information):
• The museum, which is in the High Street, is dedicated to natural history.
• This sentence means that there is only one museum in the area, and it happens to be in the High Street.
• Got it? Good!

‘If’ sentences:
In sentences containing the word ‘if’, the need for a comma depends on where the ‘if’ is.
If the word ‘if’ is at the beginning of the phrase, then we need a comma where I just put it.
We don’t need a comma if the ‘if’ is in the middle – like this.
Easy isn’t it?

Linking words and phrases:

• Linking words and phrases include: However, therefore, for example, in fact, etc.
• If they appear at the beginning of the sentence, they should be followed by a comma:
• I really should work tomorrow. However, we can go for a picnic if the weather is good.
• In fact, we could even go camping.
• Of course, we have options! For example, we already have two alternatives for transport.
• Of course, we could send the goods by road instead of rail.

If they appear in the middle of the sentence, you need two commas – like this:

• I really should work tomorrow. We can, however, go for a picnic if the weather is good.
• We could, in fact, even go camping.
• We already have, for example, two alternatives for transport.
• We could, of course, send the goods by road instead of rail.

Subordinate clauses:
Sorry! Another fancy term to confuse you. A subordinate clause is simply a phrase which is less important than another in a sentence. Basically, it is the result of two ideas being joined together into one sentence.
Idea 1: The train had left the station.
Idea 2: I arrived at the station.
Put them together: The train had already left when I arrived at the station.
The main idea here is that the train had left the station, the subordinate, or less important, the part is that I arrived at an empty platform.

If the main idea comes first, then no comma:
The train had already left when I arrived at the station.
The goods were already damaged when we opened the package.

If the subordinate, or less important, comes first, then we need a comma:
When I arrived at the station, the train had already left.
When we opened the package, the goods were already damaged.

Lists and multiple adjectives:
Careful attention needs to be paid when using commas to separate list items. Now then, read the paragraph below and really pay attention to where I put my commas. There is a good reason for each one and, even though it is a long passage, they should make it easier to read.




In the UK, when I was young, all domestic telephones were big, ugly, black and heavy, and anchored by a short, thick, braided cable. We would watch American television shows and wish that we too could have their kind of phones. American phones were stylish, rounded and available in blue, green, yellow, white, red, and even black. (Note: 6 choices) The receiver was connected to the body by a curly, not braided, cable, which matched the color of the phone. There were even two-tone phones available, in light-blue and dark-blue, and light-green and dark-green. (Note: 2 choices, not 4)

Pausing for breath:
If a sentence is very long and complicated and never seems to be coming to an end, then you can use a comma in the same place as you would pause for breath when speaking. It is also possible, and advisable, to break up a very long sentence into two separate ones. This is particularly important in modern business writing, where your reader may not have English as his first language.