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.
Dates
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.
Numbers
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.
Names
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.
This post is part of the series: When to Use Commas: A List of Comma Rules
Confused by commas? These rules for comma usage will teach you how and when to use commas. Includes information about items in a series, introductory phrases, and comma splices.
