Incorrect punctuation not only changes the meaning of your writing, but it can also cause your reader to lose focus on what you are saying. Instead, readers will start thinking about how you are saying it and why it sounds to them. They won't get you meaning, and they may not reply to your key points. Punctuation matters!

In practice

Let's look at some of the primary uses of commas in business writing:

  • Use a comma between two complete thoughts (i.e. full sentences) that are connected by a coordinating conjunction like and, but, or, yet, and so.

The email was sent on Monday, but John did not receive is until Thursday.
The expansion of our business is a long-term project, and we need an efficient management consultant to advise us.
Becky has submitted her resignation, so she will be leaving at the end of the month.

  • Use a comma after introductory phrases.

After replacing the carriage in the laser printer, please make sure the door closes completely.
As soon as we obtain additional revenue, we can buy new stock.
If you want to pass all your exams, you will need to work hard. 

  • Use commas to separate items in a list.

The committee will comprise Sue, Kara, James and Lynn.
We need to order more envelopes, paper and staples.

  • Use a comma before and after information that could be placed in brackets.

The new employee, Mary, will start work on Monday.
The new shopping mall, which opens on Monday, has 43 stores.
We need John, and possibly Doreen as well, to help with this project.

Finally, check out this sentence, which could be read in two ways

Mary, my assistant, will call you soon.
In this example, Mary is 'my assistant'.

Mary, my assistant will call you soon.
Without the second comma, Mary is the person you are talking to.