A Proofreader’s Guide to Dates in AP Style
The Associated Press Stylebook is the go-to style guide for many writers, news outlets, and businesses. And if your clients use AP style, you’ll need to know how it works. With that in mind, here we’ll look at what proofreaders should know about dates in AP style, including:
- The basic date format (and when you might need to adapt it)
- Guidelines on when and where to include commas in dates
- When, how, and where months and days should be abbreviated
- Advice about using “on” before dates (and when to omit it)
- When to include an apostrophe in decades
- What AP style has to say about starting a sentence with a year
This will help you know what to look for when proofreading documents that contain dates. For more information on all the above in AP style, read our guide below.
Rules for Writing Dates in AP Style
The AP Stylebook has two key rules that will apply to most dates:
- Dates should be written with Arabic numerals, not words.
- Dates do not include ordinal indicators (i.e., the st, nd, rd, or th after the date).
Here are some examples of how dates look when written in AP style (plus some incorrect versions):
Goodliffe was born May 5, 1981. ✔
Goodliffe was born May fifth 1981. ✘
Goodliffe was born May 5th, 1981. ✘
If you see a date written as a word rather than a numeral or with an ordinal suffix, it will need to be corrected.
In addition, AP style suggests leaving out the year in stories that refer to the current year. For example, an article from 2024 that referred to something in 2024 would say:
The week-long event began May 28. ✔
The assumption is that the reader will know it refers to the current year, which is fine for most news stories.
However, be aware that this rule was designed for news articles and reports! So if your client is following AP style for a different type of document, consider the context and if the reader will understand the date without a year. If the text refers to something from a year other than the current one, or if the year in question could be unclear, you should advise your client to add one.
Regional Date Formats
You’ll notice we’ve used the US date format in the examples above. This is because The AP Stylebook focuses on US English, and all the examples it gives use this format.
However, the “correct” format to use will depend on your client’s chosen dialect. You may even need to advise your client to adapt the date format in some cases (e.g., suggesting switching to the UK format if the document is aimed at a UK audience).
We’ll note any further differences between US and UK dates as relevant below.
Commas in Dates
There are two situations in which AP style uses a comma in a date.
The first is between the date and the year when using the US date format:
The event was scheduled for June 6, 2024. ✔
The event was scheduled for June 6 2024. ✘
However, this rule is specific to the US date format because the two numerals (for the date and the year) are beside each other. In other date formats , the month separates these numbers, so no comma is required. For instance, a client using the UK date format would write “6 June 2024.”
The other instance when a comma is used is when the date also includes the day of the week. In these cases, a comma is placed between the day and the date:
The venue is booked for Saturday, July 18, 2026. ✔
The venue is booked for Saturday July 18, 2026. ✘
This rule still applies even if the date is written in a different format (i.e., it applies to both UK- and US-style dates).
The event is scheduled for Saturday, 18 July 2026. ✔
The event is scheduled for Saturday 18 July 2026. ✘
Abbreviating Months and Days
When a full date is used in the main text of a document, AP style abbreviates months that are more than five letters long (i.e., Jan., Feb., Aug., Sept., Oct., Nov., Dec.):
24 Nov. 2009 ✔
6 June 1984 ✔
24 November 2009 ✘
6 Jun. 1984 ✘
Keep an eye out for these abbreviations, plus the full stop at the end, when checking documents with dates.
And remember that is only applies to full dates. Months without an exact date are not abbreviated:
In Britain, snow is more common in February than in December. ✔
We can trace this phenomenon to January 2006. ✔
In Britain, snow is more common in Feb. than in Dec. ✘
We can trace this phenomenon to Jan. 2006. ✘
In addition, the rules are different in tabular material. In a table, all months can be abbreviated to their first three letters without a period (e.g., Jan, Feb, Mar, Apr). The same applies to days of the week (e.g., Mon, Tue, Wed). However, days of the week should always be written out in full if they appear in the main text of a document that’s following AP style.
Using “On” Before Dates
Typically, AP style omits the word “on” before a day or date:
They are set to reconvene Monday. ✔
They are set to reconvene on Monday. ✘
The two exceptions to this are when a date falls at the start of a sentence:
On 23 March, the park will open to the public. ✔
23 March, the park will open to the public. ✘
And when adding “on” will help to prevent ambiguity, such as when a day of the week follows a proper noun. For example, including “on” between the company name and the date ensures clarity:
A new CEO will join Proofreading Solutions on Monday. ✔
A new CEO will join Proofreading Solutions Monday. ✘
Keep in mind, though, that this omission of “on” is quite distinctive of news writing, especially in American English. Therefore, whether to do so may be a matter of stylistic preference for your client, depending on what they are writing and the dialect they’re using.
Apostrophes in Decades
AP style is in line with common convention when it comes to using apostrophes with decades. You can abbreviate a full decade by replacing the century element with an apostrophe:
Queen’s career spanned the ’70s and ’80s. ✔
Queen’s career spanned the 70s and 80s. ✘
As with all writing, keep an eye out for apostrophes being wrongly used with years and decades (e.g., 1800’s).
Starting Sentences with Years
Most style guides suggest not using numerals at the start of a sentence, but AP style makes an exception for years. As such, a sentence can start with a year:
2020 was a difficult year for many people. ✔
This means that when proofreading, there would be no need to rephrase this sentence.
Becoming A Proofreader
You can learn much more about proofreading in Becoming A Proofreader! It includes a whole lesson on how to write numbers, including dates, so you can understand all the options and rules. Sign up to sample two free lessons from the full course today to take the first steps in your freelance proofreading career.
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