The 12-hour clock is a method of telling the time in which the civil day runs from midnight until next midnight.
- AM (ante meridiem) = midnight to midday.
- PM (post meridiem) = midday to midnight.
The following numbers (used twice in the same civil day) of hours are: 12 (acting as 0), 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and 11, with AM or PM.
Both names are from Latin and ante meridiem, means "before midday" and post meridiem means "after midday".
The 12-hour time is common in several English-speaking countries and former British colonies (such as the United Kingdom, the United States of America, the English speaking parts of Canada or India), as well as a few other countries. There is no widely accepted convention for how midday and midnight should be represented: in English-speaking countries, "12:00 PM" means 12 o'clock midday, while "12:00 AM" means 12 o'clock midnight.
| 24-hour clock | 12-hour clock | Period |
|---|---|---|
| 00:00 | 12:00 AM Midnight | Postmidnight |
| 01:00 | 1:00 AM | |
| 02:00 | 2:00 AM | |
| 03:00 | 3:00 AM | |
| 04:00 | 4:00 AM | |
| 05:00 | 5:00 AM | |
| 06:00 | 6:00 AM | Morning |
| 07:00 | 7:00 AM | |
| 08:00 | 8:00 AM | |
| 09:00 | 9:00 AM | |
| 10:00 | 10:00 AM | |
| 11:00 | 11:00 AM | |
| 12:00 | 12:00 PM Midday Noon | Afternoon |
| 13:00 | 1:00 PM | |
| 14:00 | 2:00 PM | |
| 15:00 | 3:00 PM | |
| 16:00 | 4:00 PM | |
| 17:00 | 5:00 PM | |
| 18:00 | 6:00 PM | Evening |
| 19:00 | 7:00 PM | |
| 20:00 | 8:00 PM | |
| 21:00 | 9:00 PM | |
| 22:00 | 10:00 PM | |
| 23:00 | 11:00 PM |