Back نظام 12 ساعة Arabic 12-гадзінны фармат часу BE-X-OLD 12-часов часовник Bulgarian Sistema horari de 12 hores Catalan Taknaang 12-oras CEB AM og PM Danish 2-mal-12-Stunden-Zählung German Δωδεκάωρο σύστημα ώρας Greek Sistema horario de 12 horas Spanish ساعت دوازده ساعته Persian
The 12-hour clock is a time convention in which the 24 hours of the day are divided into two periods: a.m. (from Latin ante meridiem, translating to "before midday") and p.m. (from Latin post meridiem, translating to "after midday").[1][2] Each period consists of 12 hours numbered: 12 (acting as 0),[3] 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11. The 12-hour clock has been developed since the second millennium BC and reached its modern form in the 16th century.
The 12-hour time convention is common in several English-speaking nations and former British colonies, as well as a few other countries. In English-speaking countries: "12 p.m." usually indicates noon, while "12 a.m." means midnight, but the reverse convention has also been used (see § Confusion at noon and midnight).[4][5][6] "Noon" and "midnight" are unambiguous.
| 24-hour clock | 12-hour clock | |
|---|---|---|
| 00:00 | midnight 12:00 p.m. 12:00 a.m.[a] | |
| 01:00 | 1:00 a.m. | |
| 02:00 | 2:00 a.m. | |
| 03:00 | 3:00 a.m. | |
| 04:00 | 4:00 a.m. | |
| 05:00 | 5:00 a.m. | |
| 06:00 | 6:00 a.m. | |
| 07:00 | 7:00 a.m. | |
| 08:00 | 8:00 a.m. | |
| 09:00 | 9:00 a.m. | |
| 10:00 | 10:00 a.m. | |
| 11:00 | 11:00 a.m. | |
| 12:00 | noon 12:00 a.m. 12:00 p.m.[a] | |
| 13:00 | 1:00 p.m. | |
| 14:00 | 2:00 p.m. | |
| 15:00 | 3:00 p.m. | |
| 16:00 | 4:00 p.m. | |
| 17:00 | 5:00 p.m. | |
| 18:00 | 6:00 p.m. | |
| 19:00 | 7:00 p.m. | |
| 20:00 | 8:00 p.m. | |
| 21:00 | 9:00 p.m. | |
| 22:00 | 10:00 p.m. | |
| 23:00 | 11:00 p.m. | |
- ^ "Time". The New Encyclopædia Britannica. Vol. 28. 1986. pp. 660 2a.
"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) - ^ Cite error: The named reference
NISTFAQwas invoked but never defined (see the help page). - ^ Addington, Susan (25 August 2016). "Modular Arithmetic". Archived from the original on 4 July 2008. Retrieved 28 November 2008.
- ^ "Is noon 12 am or 12 pm?". Royal Museums Greenwich. Retrieved 26 January 2023.
- ^ "U.S. Government Printing Office Style Manual - Chapter 12 - Numerals". govinfo.gov. Retrieved 27 January 2023.
- ^ "time of day, elapsed time". Resources of the Language Portal of Canada. 22 October 2020. Retrieved 27 January 2023.