Addington, Susan (25 August 2016). "Modular Arithmetic". Archived from the original on 4 July 2008 . Retrieved 28 November 2008. Lawrence Abrams (13 December 2012). "How to customize how the time is displayed in Windows". Bleeping Computer. Archived from the original on 29 October 2013 . Retrieved 26 October 2013.

Watson, James Robert. "A more efficient way to denote am or pm". Jim Watson professor of design . Retrieved 30 August 2022.

AM". The American Heritage Dictionary of the English Language (Fifthed.). 2011. Archived from the original on 9 January 2014. The abbreviation 'AM' stands for ante-meridiem, which is the time before the meridian line has crossed the Sun, and 'PM' stands for post-meridiem, which is the time after the meridian line has crossed the Sun. How to Convert AM PM to 24 Hours? The terms "a.m." and "p.m." are abbreviations of the Latin ante meridiem (before midday) and post meridiem (after midday). Depending on the style guide referenced, the abbreviations "a.m." and "p.m." are variously written in small capitals (" am" and " pm"), [ citation needed] uppercase letters without a period ("AM" and "PM"), uppercase letters with periods, or lowercase letters ("am" and "pm" or, [13] "a.m." and "p.m."). [ citation needed] With the advent of computer generated and printed schedules, especially airlines, advertising, and television promotions, the "M" character is often omitted as providing no additional information as in "9:30A" or "10:00P". [14] The Tongue and Quill (PDF). US Air Force. 27 May 2015. p.356. Archived from the original (PDF) on 26 November 2020 . Retrieved 26 October 2021. Air Force Handbook 33-337. Unicode specifies codepoints for "a.m." and "p.m." symbols, which are intended to be used only with Chinese-Japanese-Korean (CJK) character sets, as they take up exactly the same space as one CJK character:

AM in the 24-hour format is expressed as 00:30 because we subtract 12 hours from the time after 12 noon. Here, 12:30 - 12 = 00:30. It is to be noted that the hours and minutes remain the same from 1:00 AM to 11:59 AM. Is Noon AM or PM? Question 4-1) Is noon 12a.m.? Or 12p.m.?]. National Astronomical Observatory of Japan (in Japanese) . Retrieved 19 January 2022. Trudgill, Peter (17 May 2020). "Number five-and-twenty: A fading linguistic practice". The New European . Retrieved 13 October 2022. Time". Encyclopædia Britannica. Encyclopædia Britannica Online Library Edition . Retrieved 20 November 2013. The use of AM or PM to designate either noon or midnight can cause ambiguity. (subscription required) For different opinions on representation of midday and midnight, see #Confusion at noon and midnighta b Chicago Manual of Style (17thed.). University of Chicago Press. 2017. paragraph 9.38. ISBN 978-0-226-28705-8. Although noon can be expressed as 12:00 m. (m = meridies), very few use that form. Some style guides suggest the use of a space between the number and the a.m. or p.m. abbreviation. [ citation needed] Style guides recommend not using a.m. and p.m. without a time preceding it. [15] a b c d "Times of Day FAQs". National Institute of Standards and Technology. 21 September 2016. Archived from the original on 21 September 2018 . Retrieved 30 September 2018. In describing a vague time of day, a speaker might say the phrase "seven-thirty, eight" to mean sometime around 7:30 or 8:00. Such phrasing can be misinterpreted for a specific time of day (here 7:38), especially by a listener not expecting an estimation. The phrase " about seven-thirty or eight" clarifies this.