Are AM and PM Capitalized?

There’s a lot of confusion surrounding “AM” and “PM.” Are AM and PM capitalized? Do you write them with periods or without? You’ve come to the right place.

What Do AM and PM Stand For?

AM stands for ante meridiem and PM stands for post meridiem, which are Latin phrases meaning before midday, and after midday. When it comes to abbreviations and acronyms, these letters should be capitalized. Just like you’d write BBC, NBC, or your ABCs, AM and PM should be capitalized.

Are AM and PM Capitalized In Sentences?

Regardless of where or what you’re writing, the consensus is to capitalize AM and PM.

Like these other acronyms, that also means you should leave out any punctuation or periods. Here are some examples of sentences with AM and PM.

  • I woke up at 5 AM to go for a run.
  • Let’s agree to meet for lunch at 3 PM.
  • Did you say the movie starts at 10? Is that AM or PM?

Here are some common mistakes and incorrect examples.

  • Is the game at 9 pm?
  • He wakes up every day at 10 A.M.
  • She called me last night at 6 p.m.

Notice that some of these examples are commonly used, and may not stand out as being wrong. People often lowercase AM and PM in casual or informal writing, so it doesn’t really matter how you stylize them. However, for formal publications, essays, and books, AM and PM should be capitalized.

Are AM and PM Capitalized In Titles?

These rules also apply to titles. In titles, words over four letters, in addition to words that are important, are capitalized. Although AM and PM are two letters in length, they should be capitalized in a title.

Here are some examples:

  • 5 AM at the Airport: A Novel
  • We Met at 3PM That Day
  • I’ll See You in the AM

There you have it. Is AM and PM capitalized? The answer is yes, no matter which way you cut it.

To learn more about proper title capitalization rules, give our free title capitalization tool a try.

Capitalize My Title is a dynamic title capitalization tool used to make sure your titles or headlines use proper capitalization rules according to various style guides include APA, AP, MLA, and Chicago. It also counts your words and checks for grammar issues.


  1. Hello,

    I’m curious as to how you came to the conclusion that a.m. and p.m. should be capitalized without periods when APA, Associated Press, MLA, and Chicago Manual of Style all say that lowercase with periods (the way I wrote it) is correct? Barring, of course, the caveat by Chicago Manual of Style that it is okay to capitalize the two only when it is with periods and only when it is small capitals.


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