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Miscellaneous Rules of Comma Usage

By Keren Perles

The four comma rules we’ve already covered apply to a broad number of situations. There are some less well known more specific rules about using commas with dates, place names, and numbers that we'll cover here.


When a date is written traditionally as month-day-year, a comma should be placed between the day and the year. For example:

  • July 4, 1776

When a traditionally-written date is inserted into a sentence, an addition comma should be inserted after the year. For example:

  • On July 4, 1776, the United States declared its independence.

Alternatively, these dates can be written in the British style (also common in other countries and the US Army):

  • The United States declared its independence on 4 July 1776.

When the day of the week is added, put a comma between it and the rest of the date. For example:

  • On Tuesday, March 16, we will be going on a field trip to the National Museum of Art.

Place Names

Always insert a comma between a city and state. In a sentence, insert a comma after the state as well. For example:

  • Last year, we traveled to Cincinnati, Ohio, for a three-day conference.

When you are writing a complete address in sentence form, separate all elements of the address except for the zip code and the element that precedes it. For example:

  • Myra addressed the envelope to Sally Rosen, 43 Open House Ave., Baltimore, MD 21209, and sealed it shut.


When writing numbers or prices that are more than four digits, insert a comma after every three digits from the right. Some style guides require a comma for a four-digit numbers as well. (This does not apply to zip codes, page numbers, or most dates.) For example:

  • The house cost $240,000.
  • There were 35,000 people at the rally.


If a name is followed by an academic degree, the name should be separated from the title with a comma. If additional words follow the degree, the degree should be followed by a comma as well. For example:

  • Paula Wanger, PhD, will be speaking at the conference tonight.

Although some style guides specify differently, most people do not include a comma between a name and a suffix. For example:

  • Martin Luther King Jr. is one of the most famous supporters of human rights.
  • Richard III became king of England in 1483.